Originally posted by Josch:
Well, I removed the one at the rear, and added a new elbow section of pipe and installed an oval chrome resonator tip off of a wrecked Porsche944 onto it. And I left the muffler/ resonator (?) unit that is in the middle of the car installed. I really like the sound now though. It has a very deep low sound (due to the long hollow tailpipe that leaves the first old muffler. It does have a rasp when cold though, but when warm, it sounds really good and the rasp is gone. I just use that as inscentive to never get on it until it is warmed up (engine lasts much longer anyway if you don't beat on it when it's cold)
I took a similar approach to you, except I replaced the rear muffler with a spiral muffler similar to the Moroso:
Moroso Spiral Flow muffler 
The sound is louder than stock however it does not have the loud deep bass of an SVT exhaust without resonator or with resonator replaced by a glasspack. It does have a more aggressive, higher-pitched throaty tone which is unlike any other Duratec I have heard. According to Moroso, that muffler design employs noise cancellation which is something that would affect the lower frequencies more. Hence my lack of deep bass. I would like to try replacing the resonator with a high-flow muffler/resonator in the hopes of deepening the tone but without making it too much louder overall.