I see this post is old but... I live in Phoenix and tried the RR for track days on my Elise SC. If you read up on the RR tire you will find that the tire does well between 27-33 and 38-41psi. 34-37 is no mans land and it SUCKS. The trick to our cars is that they are so light that it is hard to get and keep heat in the tires. I started at 27 and let the pressures build up and rarely got to the danger zone. They are GREAT track tires and lasted us 6 weekends without seeing much drop off. If you are beginner driver I'd say you could get 10 or more on them. Even if there tread is gone, the tire still sticks pretty good. If you are going to run race group, I'd say 4 weekends is a good prediction and 5 if you aren't real good. I've got a lot of race experience and I let my buddy (HPDE guy) run the car when I thought the tires were done and he thought they were still like new. So, it all comes down to how hard you drive them but for the money they are the cats meow. For comparison, we ran NT01's, 888's, and few others and have decided to run only rr's until someone comes out with the latest and greatest.
My comment may have passed the expiration date but hopefully it will help you guys in the future that are reading this. I welcome other folks thoughts after they try them!