For the most part this is going to be a factor of your driving style. Some like to enter a corner fast, and carry the speed...Others prefer to come in slow and exit under acceleration. Either way, the tire pressure that suits you best is something that you'll have to toy with over time.
That said, I can offer my experiences as a baseline. When I ran street tires, I usually started at about 45/35. Track conditions would dictate from there (i.e. damp/wet = lower hot/dry/grippy = higher). I have tried as high as 52, but 45 seemed to work best for me.
The front is usually the easiest to get right for me. The back steps out only under really hard cornering or slolams, and that can be tricky to get just right before my last run.
I have had no problems running my tires at above 50psi. I don't know if there is a max psi rating for my tires.
Good Luck,
Mark
