Limited slip diffs make a huge difference - I had one on an Alfa 147 and if you planted the throttle mid-roundabout, it would pull in tighter. Quite a strange sensation but one I did not get bored of.
Also, 9" wide slicks help on race cars
with TCR and NGTC being 350-400bhp, that isn't a great deal more than you can get on FWD road cars (Cupra Leon for example)