This sort of depends on where youtr tire pressure is to start with. FOr street tires (not DR's) you just need to maximize the amount of tread hitting the road. This should put you in the 30 PSI range. I wouldn't go below 28 or higher than 31 for stock Goodyears. Too high a pressure creates a crowning effect in the middle of the tire and wears out the centers (less tread on the road also) and too low creates cupping (lifting in the middle with more weight on the outside edges) and actually has less tread in contact with the road surface. I quick check for pressures would be to find a loanly road and do a few starting line launches. Pick a place that you can spend a little time and look at the tire patches you leave behind. Just lay down a hard launch and then go back and look at the stripes left behind. If the tire marks are darker on the outside edges the pressure is too low (cupping). If the patches are darker in the middle then the pressure is too high and the outside edges aren't making good contact with the road. Best pressure should have even tread pattern across the width of the patch.