yea 33 is WAY low... i run that up front, 32-35 and 40 maybe 40+ depending on surface's grip. your tires will roll over themselves at 33 making drifting much less effective.

lets say there is like normal driving psi that is like 36psi all around for tire "X", now at 33 they will grip a little better because they give to the road some and at 40 they will slide better cuz they arent able to roll on the sidewall as easily. 33 up front makes the steering more responsive with more grip and 40 out back will allow for them to slide smoother and more consistent. however if you lower it too much you will lose all grip because the tire will roll over the sides like crazy. these numbers are not for every tire, but you have to play with what you have to fit your stlye. the profile of the tire can also effect what psi to run, the smaller the sidewall the more resistence to rolling onto it.

also look at the manufacture's suggested max psi. some are 40 some are 44, i personally dont over inflate because im not sure how much extra psi i get from heating the tires(and the air inside=more pressure) from drifting and dont need any kinda of problem.