If I may make a few suggestions (this might sound like a broken record) on transeversely mounted V6's- they never sound quite right like let's say a Nissan 350z (
).
The problem is not in the mufflers, cats or resonators. The problem comes from the front 3 cylinders having longer tubing than the rear 3 cylinders (unequal length header). No matter what you do after the headers you always end up with the same annoying V6 raspy gurgle. How do you fix that?
Make a block off plate for the rear header (where the downpipe comes out) and have the crossover pipe reworked so the exhaust exits at the center of the engine, making the front and rear cylinders to have equal length pipe before they merge into one pipe (will look like a turbo crossover pipe minus the turbo). Then you need to make a downpipe that connects back to you stock exhaust and the car will sound amazing, even with the rest of the exhaust being stock. Only then you can start experimenting with mufflers and tune the loudness of it. Currently my turbo L67 has perfectly even length secondaries and all I have is a single glasspack on a totally straight pipe. The sound is deep, nicely reverberating into resonance between 2200-2800RPM. I will post a sound clip soon so you can see what I'm talking about.
So from a sound point of view it's relatively cheap to mod the header and have a very nicely sounding car, no matter if it's a 3100, DOHC, 3800 or anything in between. Equal length secondaries holds the key.