Quiet muffler recommendation.

[formula_raider]

I know this subject will bring alot of different opinions but I just thought I would give it whirll!
I am ready to put in my exhaust system, after a full engine build up. I am going with a 2 1/2" dual exhaust with long tube headers. I am running the exhaust through the body infront of the rear tires. I am really concerned about the noise because the outlet of the exhaust. I want something that has a nice tone but not loud or alot of resonance. I had flowmaster 40s previously and they are way too loud. I am debating between the flowmaster delta 50's or possibly the new Magnaflow 3-chamber XL Turbo muffler. Anybody have a good suggestion. I still need it to flow well, I will be pushing over 400HP.