The only thing that I can think of (without standing beside your beastie) is that there is might be some backpressure in the exhaust system that is causing your grief .. take it back to the muffler shop and have them check it over.
Another thing is the size of the pipes used .. do you have a Y or H pipe happening, or are you running complete dual with no cross-over? I am using dual exhaust with no cross over, and have no lack of power (for now
Hello, my name is Vance and I am a Jeepaholic.
Its better to be naked with your friends, than to be clothed with your enemies
Silver 2006 TJ Unlimited
, zombie ready as the daily-driver