f1o7x9- regarding the pistons, how are they not smooth? did you check them to see if they had any rough edges? They should be just as smooth, if not smoother than the stock units. If you feel like you received some defective ones, I will replace them free of charge.
You should not have to sand anything though. Double and triple check that it is the pistons and not something else that is causing this. Not saying it could not be the pistons though. Sometimes, stuff can be out of spec.
mtbboy- I have a couple of set-ups on the thread here somewhere. What surface are you running on? I need to know so I can point you in the right direction.