I know that this may sound stupid but I took my zrt 600 out and it is running the best it ever has. I was trying to get enough money saved up to finish putting my 700 big bore kit in it but I didnt have enough money to buy pistons. Which that is the only thing I dont have I already have the jugs for it. But anyways all I did different to my sled this year is put my milled heads on it. Which the milled heads must had helped alot because the thing runs great. Which scares me knowing that something has to go wrong because it runs so good. Does anybody else ever feel this way?