I have the Fister modification which is essentially the Pedro mod. Sounds great, with no drone. I am completely satisfied and would highly recommend this mod. The cost is minimal compared to a new muffler.
http://sfbay.craigslist.org/eby/pts/1056416416.html
The 911 version is pictured. The Boxster version is similar to the others pictured in previous posts. Daren was a pleasure to deal with.