All the mechanics in my town, Ithaca NY, look at me like I have lobsters crawling out of my ears when I ask them to cut off my muffler, and replace with a Y pipe. I tried 4 places.
So, I decided to do it myself. I've seen cleaner results by other members, but for about $70, I got what I wanted. Here is what I did:
Cut the muffler off leaving a few inches in case I wanted to put it back on. See pic.
Purchased an reducer from NAPA #EXH 41999 - about $20

Purchased a Y pipe from JEGS through ebay - Jones Exhaust U4-4 Aluminized Stamped U-Pipe 2.5 Inlet 2.5 Dual Outlet 6 Outlet - about $20

Purchased 2 tips from Auto-Zone #PM-1050AZ, total $30

The trick is to set one of the tips on an angle so it "appears" to exit the rear straight and uniform.