there is no substitute for strength and SAFETY ,safety being the big word,the extensions are for looks and most carry a warning about the amount of weight they can carry and it is far less then the bike was designed for having and arm built or your factory arm added to professional is the only way to do the bike. i have done several with 8 inches in them and the guys love them next to no chance of doing a wheelie and fan the clutch all you want ,but the lighter the rider is the less arm he will need ideally because of weight transfer and the bike being able to spin the tire easier with less weight on it, but the fast bikes also use the art of the left hand to get the bike out of the gate and not drag the motor down when leaving ,much like a slipper clutch but alot cheaper,and if you can do that you will also need less arm . right now you just let the clutch go and up the front end comes? then your not really riding the bike you just there to hold on and letting the bike do what it wants.ther are guys in the all stock class that can do one helll of a hole shot with no arm at all,look at ryan schnitz on his little bike,check out all your avenues its the little things that make the difference in racing. have a good one and let me know if i can help you with the arm work i would be glad to help. take care cya btk572