Thanks Paul!
This was the reason I asked: based on the "November 6, 2007 NASS Perky OTS Speed Rules Reviewed and approved by NASS Technical Director to ensure compliance with AMA Safety rules. 7. No Tuned Pipes or Megaphone exhaust extensions allowed. Mini Pipes and Mufflers are ok.
Lastly, does one have to use the upper cowl?
Jim "World Perky Speed Champion" Carter
(Hey .... don't wake me up .... a fellow can dream can't he?? )