I have an 09 290 EVO, and i ride mostly at high altitude 7,000'- 11,ooo'. Also i weigh 250 lbs. or about 17.8 stone. I was considering a different exhaust to get some of the bottom end snap back, but I didnt want to loose the silencing qualitys of the stock header or the fact that it stays cool and dosent burn holes in my riding pants. So I ended up trying a set of the Boyeson pro series reeds part#112. These reeds are different from Boyeson's power reeds in that they have a thick lower petal and a thin upper petal. In use i noticed that the bottom end power became flexable and easeyer to use. I think the motor spooled up slightly slower, while the torque became slightly more and the motor could drop down farther in the RPM's without concern of a stall. I also added one of their power wings to the carb inlet which added more torque and made the motor a little bit more lively. " The motor will now spool up a little quicker" Both of these mods together cost about $160.00 and added plenty of torque. I had to lean out the air screw 1/2 turn with the addition of the power wing.