Guys,

I'm at a loss as well.. common sense tells us that less backpressure equals benefits, not negative results!... but...

All I know is that when I went with the Flowmaster Super40, which has much more open flow than stock, I lost a lot of low-end torque, some hp, and gas mileage was terrible. (also confirmed by VCross007 when he tried the same setup)

I put the stock muffler back on, and everything was great again... but too quiet.

So, I found a happy medium... a similar design (chambered), but with fiberglass surrounding the chambers (which should add some resistance).
So far so good! Throttle response seems improved. Torque is GREAT. Gas mileage (so far) is definately improved.

So, I don't have any dyno data to "prove" it... just experience.

I'd also like to apologize to VCross007 for leading him to the Flowmaster prematurely...

Littlebeast,
RE: "I am looking at 3 options:
-MagnaFlow part# 14378
-Cherry Bomb part# 88115
-FlowMaster 50 Series SUV part# 524554"

My Cherry Bomb Vortex part number is 88101.
Also, according to the muffler guy, the FlowMaster 50 series is pretty quiet... almost like stock with a little bit of a "throat" to it.
(I never looked at the MagnaFlow... always heard they were too raspy/loud)

I'll try to get a sound clip soon... maybe today.
Thanks!