The pipes are very close.....inside and out. Some very minor changes create a different band width or peak torque spot. To me, band width and how it pulls through the range with different throttle inputs is what I am looking for. Max numbers can be so misleading. Many people play with flex lengths and such. I can usually get the power to the track. Getting that great band width is just more important. The start of the race can be win or lose for the race. I don't know how many times I've seen a kart be fine until they get really slowed down in the corner and when the clutch engages, around they go. This is exactly what Jack speaks of when he mentions the "package".