ive found with anything over 770 cc that running the top screw open a good bit,"amount open dependant on cooling setup" and all other screws closed I pick up a ton of low end response and hit,a loss of upper mid and top end,but we hardly ever use it in freestyle/freeride anyway with a p pipe.This has worked wonders on 3 diff larger motors,doesnt seem to make anywhere near as much effect on 701 motors espec when the mani and head pipe have not been opened up.A hot pipe doesnt do much for our kind of riding at all,some extra rpm dont mean didly if you never get up top to use it. another advantage to this setup is the motor runs much cooler,the jetting can be smaller and the timing can be even further advanced with programable ign for yet even more low end response.