I run the proline shocks with the 3.3 stuff dont have an issue. Are you using the RPM arms or the stock. Im using RMP. It is a fairly tight squeeze with the proline shocks. What shock towers are you using, and which holes in the arms? I had to get the little pegs on the shock towers just the right length to get it all to fit together just right.
Just for reference. This thread has a photo of my maxx with the 3.3 stuff all set up before the I went to the proline shocks.
http://www.rc-monster.com/forum/showthread.php?t=3588 WhenI shitched to the fatter proline shocks I had to get the spacing right on the upper shock mounts.
If your shock cups are rubbing on the slidders maybee a small washer between the shock mount on the arm and the hollow ball at the bottom of the shock to move it out just enough to clear the slidder.