:TY: My friend is basically a parrot. if repeats whatever he hears and i usually set him straight. i remember reading an article in 5.0 mustang a few years ago, a muffler shootout on a mildly modded car. they tested everything from borla xr1 to super turbos. the realization reached afterwards was that all of them tested were within a +5/-5 hp tolerance to each other, same for torque. muffler choice seemed more for exhaust note than power levelryclef331 said:I don't know about fuel injected cars HOWEVER...there comes a point when a chambered muffler IS a hinderence to the production of power and a flow-through muffler will net substantial gains. Just recently witness the removal of a spintech pro street muffler switched to a flow through magnaflow race muffler....over 20hp was picked up.