I have the cat back system from MAC. It's really well built and looks good too. Since I installed 1 3/4" SLP stainless headers it has gotten an annoying raspy sound to it (almost like a glass pack).

I was thinking of ripping out the resonator that's welded inside the tailpipes. That would leave a 2 chamber muffler with two 3 1/2" by 2 foot long straight pipes... has anyone done this before or has anyone got twin 3 1/2's on their car?

 

My buddy has a 89formula that has 31/2pipes straight back. He had to put a muffler on them to quiet it down. Now it sounds good nice deep rumble. if they are done good and look good your two 3 1/2" by 2 foot long straight pipes. Should be ok.

 

It will be a lot louder if you pull the resonators out of the tips, unless they are blown out already (the fiber packing inside them).

Muffler tip sound is influenced by the size and shape of the tip. If a tip is larger than the exhaust piping, it acts as a megaphone and increases sound pressure levels. Also the shap of the tip can alter the sound pressure waves and make different 'tones'.

What this all means is that every type and size of tip will have an influence on the way your engine exhaust sounds and it pretty much is a hit and miss deal until you try something ans see how you like it. The only other way to know is if you can listen to a buddies car that has the system you are thinking about.

 

I realized something after posting this...

The muffler is a 3 chamber design... otherwise it could not have one pipe out each side of the muffler... just FYI