Licensing - The game should include a list of carmodels and engines that are already designed and based off a selection of real car and engine designs. You can license them (cars and enfines) or build a car using used engines (low-scale only), buit it would cost. On the other hand, it would not need any deign costs.
Fibreglass unibodies - There should be an option for crearing a fibreglass unibody construction. It would be stronger than steel, but have all the other differences between fibreglass and steel that are present,
Swing axle suspension - There should be a front (twin I-beam) and rear swing axle suspension. The sway bar options should be:
standard swaybars and types of them,
De Dion tube,
transverse leaf spring (2 last only for the rear),
Solid axles - There should be a front solid axle option in a leaf spring and coil spring variant, as such construction was or is used on many offroaders, like Jeep Wrangler, or Toyota Land Cruiser,
Front longitudinal engine FWD - The game needs an option to have FWD with a lonitudinal engine, placed either behind, between or in front of the wheels,
Two-cylinder engine - There needs to be an option to build 2-cylinder motors, in flat-2 and inline-2 configurations,
V4 engines - A 4-cylinder V engine option,
Straight 8 enignes - self-explanatory,
Camless valvetrain - an expensive, yet low-friction valvetrain that uses hydraulic actuators in place of camshafts,
Hybrid powertrains - an engine add-on that can add extra power and lower gas mileage. Available in parallel, mild and plug-in versions.
Superchargers, twin superchargers, twin/triturbo single bank and single/quad turbo 2-bank engines,
W8, W12 and W16 engines with supercharging, twin supercharging, single, bi and quad turbocharging,
Turbos inside the V,
Solid particle filters - specially good filters for the exhaust,
CVT transmissions - transmissions with a single, variable ratio,
Automatic clutch/semi-automatic - transmissions thst either do not need using the clutch or are manuals, but with automatic gearchanges,
Diagonal and radial tires - an option to have either type, with diagonal being cheaper at a cost of worse handling,
Outsourcing - an ability to have duties such as CNC work, leather preparation etc. done not in your factory, but in a separate company - at a cost per car,
A lot of those things are already being added after the new engine is added and when they make the game more shiny. The bugs, campaign, and new engine are the main priorities I think.
All of your engine questions are answered in the FAQ. I would recommend that you use the search function to find the answers to as many questions as you can. Most of them have been. Come back later.
As a general rule of thumb, if your idea is so obvious and ground breaking, probably has been asked before, or there is a reason why you don’t see them implemented yet.
fiberglass body and suspension parts —> the currently consensus is that if it is a common and relativaly modern option, it might end up in the final game. HOWEVER, there are cases where old technology is not worth to add it to the game (as no-syncro gearboxes or crossflow head designs) because you will only use it for a few years and are currently old technology to actually invest time modeling it.
Solid axles – I seem to remember that will be eventually added to the game.
Front longitudinal FWD – is already added in the open beta
Options in the engine designer – Most is in the FAQ
Confirmated engines:
L3 - L4 - L6
V6 - V8 - V10 - V12 - V16 (for some of the first buyers, for the rest of us DLC)
Boxer 4 and boxer 6 (no flat engines)
Again, some other options are not that common for road legal cars, which is what the game is about, but the devs are open to release them as DLC, after the full game is finished.
Solid particle filters – you need to check the LDU videos in youtube about the engine designer overhaul.
While not in the FAQ IIRC, I was told that 2 cylinders engines MIGHT be added to the game before launch as the new assets make it super easy to make the art assets. And they are common enough IRL.
Probably won’t be in the base game due to how rare they were.
Doesn’t exist in production engines within the game’s timeline, or at least not in common enough applications.
There is a forced induction revamp planned later on.
IIRC those are planned.
The sequential transmissions in-game are essentially that.
The tires already get better with time, somewhat representing this. And quality makes them better at a fixed point in time.
And as others have already suggested, please use the search function, as it would have answered many of your questions.