If I had to estimate the hierarchy of what made the difference in terms of net gains, I would say: 1 the cylinder head, 2 the fuel injection or TB's, 3 the cams, and 4 the exhaust. That would be my estimate based on visual assessment and specifications, but again, this would just be my estimate. In the old days I would make changes one at a time to really determine individual component values. Some things are more important than others and some add no value to a given configuration. In my old age, I am looking forward to riding more than working once the weather breaks. So I just drew from past experiences and touched what I thought needed help. In any case on initial disassembly, I was very optimistic about the potential of this little motor as it pertains to making a few extra ponies without selling the farm. Great bikes for such tinkering or anything else one wants to do.