Here are some pics of my ragtop. I've had it nearly a month and still haven't gotten my permanent plates! Only mod so far is the GT muffler. I'm really loving it, it's such a pleasure to drive! I don't think this will be my last Mustang
I got mine for 45 bucks plus 39 for shipping, that includes BOTH mufflers. Very good price, someone priced a new GT right side muffler and it was 200 bucks from Ford. These take-offs are reportedly off of new GTs that are being converted by Saleen, so they are basically new with maybe 15 or 20 miles if that. Most people install just the right side muffler, but at least one guy here also installed the left side muffler and now has duals. I will be doing the same thing with mine. It's not necessary to install duals on the six, it's for the looks rather than improved performance.
As for the sound, it is slightly louder than stock and has a nice, deep tone. Frankly I am amazed at how much it sounds like a V8. At low throttle (idle and cruising speed) you can barely hear it, but under acceleration it sounds great. If you do a search on the forums, some people have posted sound clips of the six with the GT muffler.