[gdog1977]

have searched long and hard for the perfect exhaust setup for our Northstars. Nothing substantial, alot of different opinions. You hinted that it really dosen't matter as regards to backpressure, that the 4-valve excells with a lack of backpressure, and the OEM cat is not the bottleneck. Exactly what part of the exhaust system is the bottleneck on the 4.6? What size piping and muffler would you use for maximum performance? I'm looking for a somewhat quiet exhaust system (no droning) but, exhaust flow is more important than anything else. Meaning, I will buy a loud exhaust if it's going effect performance (flow). However I do not want to buy the $1100 Corsa, too expensive. Your replies and others would be greatly appreciated.