Do you mean tuned with an Air/fuel meter when you say "sniffed"?

 

yes the shop i went to they used an O2 sensor in the silencer and helped trim my quad accordingly it worked well actually it was my first time using one i was very impressed

 

yeah man, lose the commander 3 and get the 5. they have O2 sensors u weld into the header, and it will automaticly adjust the fuel settings so that it runs perfectly. and as far as bore and stroke, its kinda worthless, just get oversize valves and porting of the head and throttle body, and with the piston u should run about 106-114 octane, keep it from burnin up, haha. and lightening the flywheel gives u more top end, and makes it rev like a bike

 

another thing that i've heard of is knife edging the crank, it helps it cut through the oil easier... its really expensive though, trust me, im gettin it done to my 300 haha