I just purchased my new '05 midnight warrior about 6 weeks ago. And am already suffering from severe case of modifyidus. I have done the BAK, jug hugger pipes, PCIII. Am giving serious consideration to puting the H.C. pistons in. I am certain it is an upgrade that is well worth the money. What the real question is how much of a difference do they make? And is it a job That is better left to the trained wrenches to do?