Really guys? Really?
Have ya even looked at the OEM muffler on an 05 or as the OP has 06?
Its straight through!! Its a bloody resonator!! Same kinda muffle ya see on Harleys... straight through resonator some packed more with noise reduction then others. the cat is like a tube and shell boiler there's yer restriction!! Hard to get a straight linear pipe from the turbo out to the tail pipe!! Straight pipe is cat delete, remove the cat install "straight" piece of tubing in place of the discarded cat! OEM muffler is straight through, unlike some car mufflers which have the inlet and outlet kitty corner from each other. Those are not straight through, they have baffles to direct the flow to aid in producing some back pressure as required by gas engines! Diesel engine is like an air compressor air in - air out...install a 5" straight pipe (cat delete) any "muffler" resonator yer ole heart can take and install a Smarty Jr. and tell the rest to suck an egg!! :p
