more rpm
 

In an effort to get more top end I'm planning on: running a shorter header, dropping from 25% to 16%. How much of a difference is there in top rpm by doing this?

It looks real shiny, and you have to try it if it works. In general the crank is balanced wich you can see with the 2 weights pressed in the crank. Grinding will unbalance it and maybe it will get you less rev`s in stead off more.:rolleyes:
putting a extra headshim will lessen the compression and the engine will rev easyer. Also some exhausts rev higher ,like the letatest Hipex low noise. Its really noticeble. Hope it works and have fun.