If it was me, I would take it to a DESCENT Exhaust / Muffler shop and have them bend and weld you up a whole new setup. Easier said than done of course, but here'* what I would do:
1) If you can find Series I headers for a descent price, start there
2) Come off your headers into a descent sized downpipe (3" MAX)
3) Get a High-Flow Catalatic Converter, and have them weld it in
4) Have them run descent sized pipe both in and out of the cat, and then have them
bend it to match your stock exhaust.
5) Have them weld on all your mounts, etc.. back onto the pipe so you can use the stock
hanger locations, etc..
6) DO NOT replace the resonator with anything, leave it off and bypass that with
7) Find yourself a good sounding High Flow Muffler for our cars like the Magnaflow or
Dynomax I think it was that people were saying sounded good (ask boseman).
I would replace the muffler just like a stock one, with a good sized pipe coming in from one side, and then the duals splitting out both sides, but smaller (2.5") You dont want to get the air flowing TOO freely, like removing the cat AND the Resonator AND getting a high flow muffler. You'll end up loosing backpressure and actually it will end up slowing you down (ask skza). If it was me I would just bite the bullet and get the high flow Cat. That way your covered for emissions and everything, and it will help with backpressure and in making that deep rumble sound through the muffler.
Just my $.02
PS - If you do your exhaust up like this, you better damn well be planning a CAI and pulley swap soon!
Your car will haul ars.