I have access to used slicks - BFG R1 225/45/17 - from a pro mx5 cup team. These teams use them for one race and throw them away, so the tires have a lot of rubber left. I am considering mounting a set on the factory 17" rims and using them for HPDE's or practice days, but I am not sure how stable the car will be with such a skinny tire on the track. Has anyone tried this before? Opinions welcome.

 

I would give them a try, especially if the price is right. I raced on 245s for a few years at 3400 lbs. Far from ideal, but it will probably work. I have some 1 weekend 275/35-18 takeoffs if you are interested in more rubber.