Originally Posted by Patch

I'd be looking at an oval muffler, like a Magnaflow or similar. Running one on my 2.0L N/A GC8 with 2" ID piping from the cat back and 1 resonator, and it's got plenty of volume, still burbles and pops when you want it to, and gives quite a nice note (not a true WRX rumble, but not a tinny ricer sound either).

Had a cannon on mine, but it was a pain on long trips - it'd echo through the entire car if you sat on anything over 2.2k RPM. The Magnaflow isn't anywhere near as bad for this - 2k rpm and you don't hear much at all until you plant it/back off the power.

If you're chasing the rumble as well, you'll probably need a set of aftermarket headers - a few pop up on Ebay now and then, should suit regardless if they say 2.0L or 2.5L.