IMO, running 15" tires isn't the big detriment a lot of people think it is either. Granted, the choices are thinning out, considerably, but there are still decent gripping, speed rated rubber out there for 15" wheels.
It's getting real thin. I don't think you can get Dunlop SP 245/50/15 ZR's any more. I think there is some other ZR stuff, but it's pretty pricey.
Seems like your Radial T/A, Firestone Indy, Eagle ST/GT, Qualifer GT... is all that's left
