I run 4" Weld wheels. In a sudden heavy rain storm I went off the highway into the median at about 70mph .....backwards ....sidways......forward ...... sideways..... backwards .....sideways ....and finally forwards again. All after fighting it back and forth across 2 lanes for about 1000 feet. In the middle of the median was a 2 foot deep ditch. Crossed that too. My 4" welds still roll straight as an arrow. I got lucky car wasn't damaged. My biggest fear during the episode was that the front wheel would fold and catch causing me to snaproll. Didn't happen.
I have a Mac Flowpath 2.5" cat-back with the new stainless tips. There a little crooked, mostly my fault trying to get around the gas tank and I got sick of it, but it's not too bad. It sounds better than the factory exhaust with Flowmaster mufflers. Has more of a lumpy sorta sound when you close than the flows had. I also like saying I have "Mac" instead of everyone else saying I got flows; makes me feel special. I can get a video clip of a rev or driving while in car if you want, 56k though, have to upload overnight or something. Since you have emissions, I would bite the bullet and go with a Bassani X-pipe that allows you to swap in the converters. If I had a lil bit more money, thatd be the way I go. I'd go with an X-pipe for a different sound compared to other pipes, and to be a little bit different since most people run H pipes.