Scratch that... 9000s would be too much after talking to Spintech. Going to try the 6000s as they are 4x6x12 or the 3000s which are 4x8.5x13 (or very close to the Magnaflow size in this thread). They didn't know if it would drone much in the car, but the muffler is designed to not drone. But you need enough muffler to dampen the sound. So the 6000s fit a little better. And truthfully, I could reuse the Kooks Bullets as resonators off the headers if needed to tone down more. But I do want that banshee wail at WOT and deep rumble at idle... with a mellow cruise. So the 6000s seem like perhaps the ticket? The Magnaflows seem too tame in comparison. But it's hard to tell off videos.
The 6000 Series is available 3" In/Out 304SS.
After my next round of "fixes" to the car, this will be what I do.
Right now, going from a 4000/3.23 setup to 3600/3.73 and installing Dynamat and getting some driveline vibrations fixed. So hopefully all of those things tone down the car some.