Sounds like holeshot is using the same slip on as they use with their complete system. Dale usually does an excellent job engineering his cans, so the lousy fit is a surprise. Usually the gain in new cans is weight, unless you get a power commander and modify the air box, then you might get a few ponys. On my Strom, I lost about 20 lbs. going from the stockers to 2 bros, but they were so damn loud that alot of the dual sport events wouldn't let me run, so the stockers are back in for now. I'm working on fabing a baffle.