like in the future? this would be very cool
not a thing, nor will it ever be a thing as the game does not support that kinda thing
(also is not planned to be added)
I’d recommend looking at this FAQ over on Steam. It’s somewhat out of date (we have parts of the turbo revamp and higher octane fuels) but cars with higher or lower numbers of wheels are currently not planned due to the amount of time and effort they’d take to do well.