I would have to agree with PaHumbug, I have the same system on H2, Its a little loud at certain RPM's, but really does sound good, especially when I kick in the ass
I would also say it didn't do anything for performance gains or fuel economy gains. I also paid around 500.00. I hope this helps with your chioce.
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2004 Hummer H2 " Metallic Red "
20 inch Mojave's (Teflon)(325/60/20) BFG A/T's
MagnaFlow kitty back...Hypertech Tuned..Music to my ears
HCMI Member 50043