i've done lotsa business w/ kennedy and he's THE most engine smart dude i've ever met when it comes to 2strokes. he knows sh*t i've never even thought about thinkin about!
he's right about the shearer pipe. it pulls HARD! my f7 had a bit more peak hp, but the thing is you couldn't really use it. you'd rip down the gear and right at the end of the gear, you'd get a boost of power (makes wheelies a pain in the ass, cuz you can't really control the balance when you're up since the throttle's so touchy), then you shift up and you have to start at the very bottom of the band again.
w/ the shearer, the curve is so strong at the front and the peak is so wide that you pull through the gear, then shift up and you find yourself still on the bottom of the peak! makes for some strong acceleration.
kennedy's port and polish job and head work will def pull every ounce of juice outta that pipe too. my blaster's like a completely different machine. i'm sure that everyone else who's got a shearer and kennedy's p&p will chime in here.