Car would be the best, which is made to common buyer / household. So it should have the latest tech.

The things in my Caprice were the best you could get in 1970s, still cool in early 1990s. Reliability and durability for example belong to the things, which were not very common in the past. Driver in distress on the road side, with broken car, was common sight. Garage people were instructed to stop and help, when they saw a broken car and driver.

Concept for new Full Sized car has :

- Custom front and back - Hardtop roof without B pillar - Butterfly doors - 4-wheel steering - 4-circuit brakes

- Digital dashboard - Foldable roof displays - New GPS - 45/55 front seat - open front floor - peltier heater-coolers

- V8 engine, with sensors - Rear wheel drive - Longitudinal control bars - Hydraulic suspension - Detailed service manual

Car is around 5.5 meters long, almost 2 meters wide.
The car is made for families. Parents and kids. 
Car differs from limo in spacing. The space weighs to front seats. 
The interior is made from plastics and fabrics. Cheaper than in limo.

New nimble concept car fits to European and Asian roads and parking places.

Custom looks

Custom looks comes from new CAD-CAM manufacturing system and 3D height maps.
System needs that you start use bolted mud covers and rear plate in the back.

In the system you can choose front and rear looks from ready made selection. Tailored and custom looks are also possible.

Custom looks allows you to go back into time right before oil crisis. You can introduce new looks to your models every year, if you want to.
Molded steel allows you to sell cheap spare parts, after you give up from looks and pressed parts.

Butterfly doors and body options

Butterfly door allows you to open the door in narrow places. In typical system front door opens from the front, rear door from the back.

Butterfly position could be optional. When so, you build upright beam for hinges. With these hinges door opens as usual.
You mount this beam to body with butterfly mechanism. Butterfly mechanism always pushes door open so much, that it can be lifted up.

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The base body for the car is hard top, without B pillar. B-pillar is only a small bump in the longitudinal beams. Bump has locking system for the doors.
After B-pillar the front-back and rear-front sides of doors are flat. In flat part another door has sealing and another surface / small hole for the sealing.

In this HT system, the whole passenger compartment is open, when both doors are open. It makes entering and leaving easier. For safety you might need a short B pillar, which prevents intrusion in side-front collisions. Alternatively you can build a broken beam into doors. So that when the doors are closed, beam comes out and tightens the middle of the body. One idea in next generation car is to increase production-retail price with useful-safe-wanted things. 

When windows are opened, the car is like traditional Hard Top. Unlike it is often said, open window does not have any effect to air conditioning.
The sensors, which controls automatic A/C,  are nowhere near windows and doors. The incoming wind has no effect to temperature sensors.

Car can have butterfly doors without HT body and vice versa.

You could take 3 body options from 1980s to use. When so, you have sedan, fastback and wagon. Coupe and convertible from 1960s are optional, just like longer wheel base.

In sedan you could give up from the upper beam after rear seat. It allows you to fold sedan's rear seat just like in wagon and fastback. When you drop the beam, sedan, fastback and wagon have almost 1 to 1 beam system. You can build the beam into rear seat's back and it's locking system. 

In Hard Top it is possible to build a small B-beam into windows. The thing, which looks like rubber sealing is actually a strong steel beam.

4 wheel steering

In this 4 wheel steering, rear wheels start to assist front wheels after turning angle is big enough. Rear wheels always turns into opposite direction.
Turning of rear wheels reduce the turning radius. Helps you drive the big car into and in small places. 

Steering acts like mechanical. It never tries to help you with steering. Aid, you can get with digital system, is always based on a wild guess from the things you want from steering and also from the situation you are currently in. Wild guesses results more often into disadvantage than advantage. Even the simple ABS system fails surprisingly often, when it is needed for real.

Therefore you should not build driving aids, which cannot be switched off line. Tracks control, which cannot turned off, is very difficult, after you get stuck into snow or mud. Need muscle power for getting the car going again. Muscle powered stuck control team does not get any help from the car. And without traction control, you could have gotten away without help. Sliding wheel has some push power and grip. Then it can dig a hole and get better grip from the harder or rougher bottom.

2-circuit electro-hydraulic steering

You might want to replace the old rods with hydraulic steering. In hydraulic steering, each wheel has it's own steering unit. Independent system can be made so, that suspension events do not change the steering angle. You can also take full advantage from new steering theory-and-geometry.

Hydraulic system is typically safer and more reliable than electric, motorized system. Hydraulic system is mechanical system, where you replace the rods with liquids.

Each unit for the wheels should have at least two independent work cylinder systems and one gear-turner system. Independent work cylinder systems keep the steering functional, when one system goes broke. 

The work cylinder at the wheel has two pipes. In chassis' steering unit you have main piston, which moves in two directions. When you move the main piston to left or right, the work piston moves accordingly. The wheel unit is completely enclosed and sealed. The wheel's turn system is covered with box. Much like drum brake. You empower and adjust the steering angles with steering box and main piston moves in chassis. The wheel's completely enclosed turn unit is better and safer then current rod system. There aren't any moving and suspending joint systems, which needs rubber covers.

Hydraulic steering in wheels allows you take full advantage from hydraulic crank-transmission system. Hydraulic pipes doesn't need much space in the middle. Hydraulic steering makes the power transmission from steering unit to rear-wheel units easy and compact. Steering forces are smaller than braking forces. Pipelines for steering are like the pipes for breaks.

Hydraulic steering detaches chassis from body. You don't need steering column-wheel system in the chassis, which goes into body. In chassis you need system with hydraulic plugs for body's standardized steering system. 

You can also use electric system in body, connect the body to chassis with electric wires. Electric system needs at least three independent wiring systems for safety. With three wires you can compare signals from the wires and drop one faulty signal from the signal, which is forwarded to actual steering unit. In cars and vehicles A/C wiring, you must detect faults in all electric lines, with multiple wires. Single wired A/C system is vulnerable to cuts and poor connectors. One poor or broken wire affects to many things.

If mechanic has played with brakes, work with hydraulic steering is similar to brakes hydraulic system.

4-circuit brakes

Each wheel get it's own cylinder and pipe line. Also possible to build hydraulic steering like 8 circuit brakes.

The ABS system is based on rotating speed. ABS activates, when wheels speed falls to near zero. Then it starts to adjust pressure and the speed of wheel. System needs to compare wheel speed with car's speed. So, that you can stop the car with brakes. Possible with for example acceleration sensor. System needs on-off switch, possible a mode for icy / slippery roads.

You should be capable of building a system, which optimizes ice-asphalt braking. Which is impossible for current ABS systems.

Digital dashboard and A/C wiring

Digital dashboard is coherent area in front of the driver, center of the dashboard, etc.
Dashboard is made with multi-display tech. The dashboard only looks and acts like it was one display.
It is made from smaller display panels.. If one panel goes broke, you can set the display into safe mode.
In safe mode all essential gauges, bulbs and all switches are moved away from the broken panel.

Typical dashboard is touch screen system, where the dashboard has switches.
Panels are mass produced stuff, used in many cars. They do not cost much.

Dashboard modules are different from common panels. They have better weather and time resistance.
Then they have heating or some other system, for bringing the panel quickly to on-line state in cold weather.

Digital dashboard allows you to build various looks and gauge sets in the dashboard.

With A/C wiring the bunch of wires behind dashboard reduces the number of wires below 10. With A/C wiring, it is possible to add and drop things from the trims, without changes in dashboard and overall wiring. You can also have add-on and third party things in the wiring and dashboard.

Typical A/C wiring has wires for input from sensors and control wire for adjusting sensors and other things. One A/C wire can carry over 100 independent signals at the time. With double wiring each sensor and function can have it's own operating frequency. 

A/C wiring needs weather-and-time proof divider for making extensions to wires. You should not simply cut the A/C wire and make simple connection systems to wires. Single wire system is sensible to poor connections. One poorly made extension for add-on high beams, can cause malfunctions in engine, fuel injection, transmission and in almost everything. Typically one A/C line has three or more wires. The system uses three signal for fault detecting. When one signal differs from  two others, there is something wrong in the wiring. The fault light goes on at the dashboard, and the system continues with two remaining signals. A/C for computers and networking has check out procedures for detecting wires conductivity / condition. Band widths and voltage differences in these two are very small. This check-out system comes to vehicles too.

Foldable roof displays

Foldable roof displays are mounted to roofs A and B-Beams. You can use bigger displays and adjust the position and angles of the display. When displays are not used, they are hidden into roof like sun visors. In the rear seat, two separate and one big display are possible.

New GPS and electric reflectors.

New gravitational GPS doesn't need satellites. GPS can use the street map and map copies from next generation web. You upload the maps into GPS. System can be automated, that it checks and updates changes, when the device and it's carrier enters new sector. When web is unavailable system uses the unchecked and possibly outdated map. Global street map has up-to date data from speed limits, road works, road-closing accidents and road tolls. Possibly also rush-data. Possible to connect GPS in to cruise control, so that vehicle never takes over speeds. Connection can be manually turned on or off.

GPS will get the electric reflector system. Electric reflectors can be made so, that they create horizontally expanded fields. So that the field extends horizontally 500 meters and vertically 50 meters or so. For mobile reflector, you can build weigh system, which keeps fields shape, regardless of the way, the reflector is positioned in for example pocket. You can also make system for pedestrians and other groups, which closes or adjusts the transmitter, when there is one nearby transmitter with the same code. Possible to for example build outline from a dense group. Sender reflector can be made with polling capability. When sender polls receiver signal, it wakes up and creates a sender field.

Cheap electric reflector increases street and road safety so much, that it is difficult to give up from them. Reflectors are essential in copter cars air control system.

45/55 front seat and open front floor.

Divided 45/55 front seat allows you to have 3 people in the front. When armrest is down, divided seat is much like arm chair. Smaller separate seats are an option.

Open front floor is needed with 45/55 seat. You can fill the space with console, when separate seats are chosen. Digital dashboard makes it easy to move things from dashboard to center console.

Car can have gear selectors in steering wheel.

V8-sensor engine and rear wheel drive

Big, five to seven liter V8 engine with latest pressure sensor tech produces enormous powers. 500-700 hp and even over 1 000 hp maximum powers are possible. Powers tends to break the weaker front wheel drive. Stronger rear wheel drive provides better grip, when you use the big power reserves.

Hydraulic suspension and longitudinal control bars

Hydraulic suspension with cruise, normal and sport stiffness setting is the most comfortable. Longitudinal control bar does not move wheel sideways. It allows the usage of longer and softer suspension. In sport stiffness they provide better grip.

Detailed service manual

Detailed service manual played a big role in Full Sized cars reputation. It made repairs easy and cars technique well known.
Negative-positive thing  is, that the manual made the car and it's tech simple. It gave you the wrong idea, that the car is simple ancient relic.

Peltier heater and cooler

With electric peltier plate you build compact heater-cooler systems. The plate cools the other side and warms the other. When you build a system, where you select the side, you can get electric temperature control system to vehicle. The plate needs copper conductor for leading either cold or heat into outdoors.

With flexible, well isolated copper wires, you can install plate systems to backseat passengers and even to trunk.