hey guys, I do some MX'ing and also a few hare scrambles a year with an occasional grass drag.when I trail ride, I ride like im in a race at all times. I'm trying to decide to upgrade my pipes or not. I'm currently running pro circuits and I absolutely love them but my fear is that they may be limiting my 421 serval a bit. they hit nice and hard down low and have solid pull all the way through. I rode my buddies ported stock cylinder 4 mil with CPI pipes and they were absolutely gutless down low- I had to keep the r's up pretty high just to ride, while the power band may have hit harder (im not really sure I wasn't hooking well) the pro circuits seem to pull for A longer period of time because they hit so much earlier. what does everyone think?