Quote from DeathItself :

Not really a new car but I would put racing slicks on STD (xfg,xrg), TBO (fxo,rb4,xrt,*lx4*) and LRF (fz5,lx6,rac). This way we could create 3 new classes or sub-classes for example STDr,TBOr and LRFr. This could offer an alternative to UFB.

Since those cars don't have wings on them I think it would make for some great racing.

+1 for slicks.
Not some crazy wide ones, but just a tad bit better than the street tyres used now.