I have used all 3 and my favorite was the proma gp, followed by the boss and lastly the bullet I am a big guy (6'2" 240) and the proma gp gives you great power in the mid range. The boss gives you great high end, but you have to wind it up to get any benefit. I myself had to fdrop the gearing to get to the sweet spot as far as rpms. Once I dropped my gearing a little lower so I could wind it up faster, the boss kicked in to give me better top speed. I used pretty much the same jet for all 3 pipes with a high flow filter. I have a kit now, so I honestly don't remember what the jet was, but I seem to think 68 with the 12mm carb and hi flow. Hope that helps you in your decisions!