Well, I picked up a set of stock RS gaskets from Michael Hohl, figuring that if you can bolt up a Stromung axle-back to a stock mid-pipe, then everything should be about the same size. . .
Everything worked out fine. We even got the spring bolts off without snapping them
So now I have a Stromung cat-back! It's nice. I love the sound, and the car feels better overall. Good stuff.
After driving Cory's car, I'm pretty convinced I want to replace the intake next.
Oh, I also got a few video clips of the car running without any cat-back on (venting straight from the cat). If anyone's interested in getting a listen, I can post them up tomorrow.