Yep, I have 2006 GT and a 1997 Civic.
But back to the Mustang.... the Stealthbox is OK and geared more towards SQ than SPL. If I had to do it all over again, I would have just built my own fiberglass enclosure and gone with an IDMAX 12. The only problem was I had to have a system in August 2008, and it was WAY too hot outside to even think about playing with fiberglass!
I am gearing up to revamp the system soon and I am going to run some relics that I have in storage right now. Soon it will be time to knock the dust off some Linear Power amps
Right now I am jealous of your Roush supercharger, but I want to do like one of my friends in New Orleans did.... He put a Kenne Bell 2.6 on his 2005 GT with a Modular Mustang Racing Lower end. He is getting 650 to the wheels and has a 175 shot of nitrous on top of that. His current block was built to handle 1,000 horsepower versus his stock block that went boom on 10 psi of boost when he just had the Kenne Belle. Too bad he was banned from the drag strip for running too fast without a roll cage