XFR-
MUST turn into a rally car! 4wd with a couple of more horses!
RB4- make it a little more powerful
XRR- make it more suited for drifting
FZ5- make it less prone to spinning out of control
UF1- Should be faster, like a UFS (cooper S)
XRT- more aggresive styling, like a R32 GTR.
FXO- XFR engine swap possible? or will it lead into understeer.
Misc:
make water temp gauge functional
proper car damage
measure fuel in litres
All tires for all cars (optional)
weather effects, not addons
when something is overheating, I'll like to see smoke
headlights should be more effective
police siren horn (for cruise servers, with police)