For more flow, what is the order of most effect to least. Header, cat, cat back? I am going to start opening some flow as my supercharger goes thru the stage 2 and stage 3. Thanks

 

the cat is the most restrictive part of the exhaust.

if the muffler is a straight through design, then the header would be the next.

 

have to start at the header. there are only 2 headers you can get that fit under a twin screw, the Jackson racing/Cobalt Performance (same header) and a shock header. loss the cat or get a spun metal if you have to have one.