I've had Sumitomo HTR ZIII on my car for a little bit in 275. They were pretty good for the price. I've done about 7 track days on them, and roughly 15k miles on top of that, until they were starting to noticably show wear. They worked fairly well at the track, although they got hot kinda quick. One thing I really did not like about them was the fact that they wore in the center quicker than sides, and keep in mind, that I did not overinflate them either.