I mainly ride the dunes, but once in a while I run some local trails, and I've got CPI's, and couldn't be happier. I have more bottom end, mid, and top power with them, than I had with the FMF Fatty's, that I used to run, on the same motor. CPI's are more versatile, than Shearers, and that's what I've been told by several builders, and racers. If you just want to drag race, then go with the Shearers, but if you want to do a little of everything, then run the CPI's.