The A compound works fine on the track. Many years ago, the Hoosier guys warned me off of them for full road course use, but apparently that's changed. One of the cars I drive (not mine) is *far* more powerful than a 355 and weighs almost as much-- my best times are on As, and they hold up fine for a full 30 minute session and survive about as well as the R compound. I haven't autocrossed in 20 years, but I assume they work better there as well.
