I just like to see alittle more meat on my tires. I run my tires 49mm in the rear and 47mm in the front to start off with. I can usually get a months worth of racing every saturday. The prizms remind me to much of CRC's High Rollers. Which leaves very little tire for me to use. I have become a budget racer lately. So the idea of running a tire like that is not feasable. I also don't have a problem with the legacy tire chunking, just peeling off the outer edge. I run them down to 41.5mm in the front and 42mm in the rear to use later for carpet racing. So they have to last me awhile.
Going fast is not the problem with the size I use. I just need driving lessons for that to get faster. That is another issue. However, I run my tires right now at club races, and they have to last since the drive to go racing cost me more in gas for the month than the tires for the 12th scale.