I'm exhausted...

[Swordy]

Has anyone else experienced a significant drop in low end torqe related to the reduced backpressure of better mufflers?

[mbeach]

Exhaust flow velocity is what provides the scavenging effect we so desire to maintain good torque -not backpressure.

Velocity is determined by design/materials. Backpressure is the result of bends/kinks in the system. Backpressure is ALWAYS bad. Velocity can be optimized by designing/sizing your exhaust system for the maximum anticipated flow.

Think of a hose connected to a water pump (after all, an engine is an air pump). When the hose is sized correctly (flow vs. cross section), the water comes out at it's maximum velocity (good). If the hose is too big, water merely trickles out (flow is fixed by the pump) =no velocity. Kink the hose (backpressure) and you just hurt the pump -you do nothing to increase the flow velocity. Fluid dynamics is pretty boring, and difficult to explain on an empty stomach. It's even harder to listen to.

Bottom line:
Correctly sized pipe, with minimal restrictions is your best bet for performance. Mufflers are there to control sound, not flow. Only crappy mufflers induce flow-killing turbulence. The perforated core MagnaFlows are a good pick. Choose a longer can for max sound wave absorbtion.

[Swordy]

I know that what you are saying makes sense, and thats what I was always told, but why then does even a miniscual leak between my cats and muffler degrade the performance sooo much?

[transio]

OMG that's an ugly setup, Cyrk!!! And LABOR INTENSIVE!!! Why on earth would someone install an exhaust that way?!? The people who did this shouldn't just refund your money, they should be arrested!!