Flowmaster or Gibson

[kevinr1970]

I am in the market for a new cat-back exhaust system and have narrowed it down to one of three systems.
Installing on an '06 GMC Sierra regular cab swb 2wd, 4.8 and 5-speed.

The first is the Flowmaster Dual Outlet Rear/Side. This is the one I'm leaning towards. Always liked the FM "sound" but am a little leary of the interior resonance I have experienced with FM's in the past. This comes with the 50 series SUV muffler - sound clip here. Seems like a decent but not overbearing sound.
The second is the Gibson Split Rear or the Extreme Dual. Best I can tell they are the same muffler but different exit location - straight out vs. angle out the sides. My preference is for the angle exit location (which I think can be achieved on the FM kit too). There is a sound clip on the first link. Sounds more raspy but maybe due to recording quality. Sounds a lot more agressive.
The third option is the Gibson Swept side Exhaust. This is a single exhaust kit. Has a lot more agressive sound to it.

The Gibson website has HP/TQ rating info for the different applications which I can't seem to find on the FM site. Their claim is that they make more usable power in the 2,000-4,000 range. They also claim to not be plagued by the resonance sound. Gibson claims to get the ~same HP increase with either single or dual but a lot more TQ with the single.
I like the idea of the dual exh. that angles out the sides but is the TQ increase worth it? Or is 10 ft pounds not worth worrying about.

Any experience with either kit? Any pros or cons with one or the other?