Cameron suggested CPI's for my riding style.
My parameters were:
Unported, running "as cast" Serval on pump gas with a minor exhaust clean up to casting flaws.
Primary use as a duner with some occasional friendly drags, short shifting and running mostly in the upper mid range.
Pipes that compliment the intended function of the Serval.
He said the torque curve is better with the CPI's for my application.
The Shearers make a couple of HP more, but you gotta rev 'em 1k more.
I bought a set of CPI's. If they don't work out for me, I'll make someone a good deal!! :-)