I agree with most of what's been said above and would really, really like to see some older cars: as someone suggested Mk1 and 2 escorts, BMW 2002, MG's etc.
I would also like to show my support for more cars that can compete closely with one another (e.g. RB4, FXO, XRT and XFG and XRG). This would give players more choice, promote close racing and keep racing interesting and enjoyable.