Thanks everyone for your great feedback
I'm going to try your recommendations to change my pistons and possibly my springs as well. I already bought the Associated front spring pack so I can run some tests.
I also noticed the same problem where the front shocks will bottom out before the chassis hits the ground. This seems to be the case when the standard mounting hole positions are used (which is what I prefer). Laying the shocks down a little more seems to let the chassis touch the ground before full compression, but then the chassis sits a little too low and the steering is affected..
Looks like I might be experimenting to fix both problems.