I have HRD porting by Mike Stiener. I have ran a FMF, Q V2 and Hall #19 on the engine. There was no loss of bottom end when moving from the FMF to the better pipes. The difference between the FMF and the other two pipes is incredible.

It is very hard to mail that money order for the high end pipe but, man, is it worth it. I have never regretted spending the money. I recommend saving up and buying a good pipe. It is the single largest performance gain you will get for the money.