A 3" single won't be nearly as loud on a turbo S2K as it is on a NA one. I really didn't mind it on my car, but I use to hate singles on NA S2K's. Just some food for thought if the loudness of it is what was making you look into getting a dual setup.

Slightly off topic, but I never understood how the SRT4 doesn't have mufflers either and still sounds relatively quiet. They do have a very strange turbo setup though where the hot side of the turbine is actually part of the manifold. I saw one a few months ago when my friend was doing a turbo upgrade on a customer's srt4 and it was pretty strange.

 

yes the SRT-4 comes stock with no mufflers... only the cat. and a resonator... straight 2.5" all the way... sad it would be too loud on my s2k