ok i get your point, but i want to add my 2cent to this "discussion"
why not having something like bonus-points. like you have 5 bonus points which you can spend on your car. e.g. 1 points for wheight reduction, 1 point for more horsepower, 1 point for less fuel consumption, 1 point for less tirewear... another driver will just push his main speed and adds all 5 points to more bhp. some other driver want to push his handling and adds all 5 points for the downforce. now this does not make sens for one race, but when you look at a league where you have to predefine your "tuning" before the first race, you have to think about which tuning do you need for a good mix on all tracks OR you just say, ok i want to win that oval race and give the BHP a push but that guy will defo suck in all south city tracks.
on short races users will always use the same setup but its the tactic on long races that brings tuning into interest.
this means, the system needs to be embeded in some sort of league structure or like ctra servers: you first earn "improvement points" and then you can spend them on your car and improve it to run with it on a league on that server.
so you get a +1 from me, but i needs a shit load of work...
i'd rather want to have a proper damage model and aero-model first though