Installed a dyno jet kit with a danmoto slip-on this weekend and the difference was crazy. Installed the jet kit using the directions included (I am at sea level) and it required no tuning at all. Kit was easy to install and easy to understand. The HARDEST part was removing the carbs. You can do it by removing the battery box and simply sliding the airbox back, after that just loosen the hose clamps holding the carbs in place and wiggle them out. Long story short, big difference and well worth the money.