Coming to think of it, I think some cars should get a facelift/upgrade for S3. 1 car and 1 track seem a tad... small. How about
A RB4 with a better interior, similar to a Celica GT4
FXO with the S1 styling kit to make it heavier and more even to the other cars in the TBO class (too fast atm)
FZ5 with 4 medium sized exhausts rather than 2 big oval ones
All cars with Updated wheel drawing system
UF1 needs a proper interior a LITTLE more power
The LX's are simple cars so they don't need upgrades, XF/XR have been updated already and the RAC is a real car, so there is no point chaning it, unless they want the 2005MY version.