Is the S muffler louder than the non-S muffler?
 

The reason I ask is that I purchased an S muffler with the two outlets to replace my stock muffler with the single large oval outlet. I like the look of the S muffler. But it just donned on me that the S muffler may be a bit more free flowing, but wasn't sure.

Plus, the S muffler I bought has been polished for some subtle bling for the back of my boxster.

Nope, the internals are exactly the same just different tips.. You should forget the S muffler if you want loud. See GHL.

If the sounds the same, then that's fine with me. The improvement in looks will be enough. Plus, I've only got $90 tied up in the purchase.

The stock muffler has a rattle/vibration sound to it when I start it up in the morning, but it goes away once she's warmed up. Hopefully the change will eliminate that annoying buzz.

....interesting Thump; mine does a similar rattle upon cold start. I assumed it was the bendix or some sheetmetal... Mine is an S.

I also like the look of twin tips, but they needed an American ear to tune the sound.

Jim