It really depends on how you are driving the car. At an auto-X I ran 35lbs on my tires and I wore out the letters on the side walls they rolled under so much. I run my tires at 40/38 every day and 42/40 at the Auto-X. That might change with my new suspension and allignment, but I would go higher than 33 if you like the corners.
I have to second croddy. The recommended pressures for the RE040's are too low for either comfort or performance. Before I went to stiff-sidewalled S-02 Pole Positions (which I now run at 39F/36R), I played around with pressures and determined that the RE040's gave the best balance of comfort, grip, feedback and even wear for street use at something like 40F/37R.
At the 2 AutoX's that I did with the RE040's I ran 45 all-around. But come to think of it, 42F/40R seems much more reasonable and could have helped squeeze out a few tenths of a second.