Are the Tru Ram exhaust headers designed for an exhaust "donut" or a flat gasket at the collector end? If you can use either, which is better? There is a lip on the inside of the collector end that I was assuming was for seating the "donut" type gasket, but if you use the flat gasket you could take that lip out to get a little better flow at that point.  
Rono 

  Ron Lane,  Meridian, ID