I have the same set up no cats LTs y to 3" out behind rear tire with Jeggs double walled 3-31/2 tip 6" sounds great but between 1750- 1875 some good drone in the cab ...but no rasp and plenty of low end ...but yea i like the drone now a little... very deep good sounding muffler i think way better then FM...passed the wife test and she would be the first to complain...lol...on my 06 5.3 HO ran Borla...hated the drone talk about drone man hated it ...ended up going back to stock then couldnt stand it so ran x pipe with glass packs true duels a little better...but load as heck and through all RPMs...so yea its hard to get it right let us know how he magna sounds to you...lol my 06 GTO sounded the best with small large diameter GP very deep and awesome sound so who knows how all this crap works out

 

look at mine. its an 18" i believe

http://www.youtube.com/watch?v=dWW-_X3kjTI

http://www.youtube.com/watch?v=2Nk-wjiQdSw

 

I found a stock uncut setup that I'm going with. The hooker setup is currently for sale.