3" or 2.5" X pipe questions

[6D9]

I currently have a Pypes 3" X pipe with 3" Super 40 Flowmasters. No tailpipes. Needless to say its very loud. plus the system hangs very low because the systems rear legs do not tuck into the rear tunnel area. So I am planning on a new set up. My motor is a 408sbc making approx 475hp. I was thinking about going with the Dr Gas X with the 3" in/2.5" out. Then running 2.5" tail pipes. Or should I just go 3" all the way and deal with the noise. Mufflers are going to be Hooker aerochambers.