go to mustangexhaust.com, im a member there wiht the same name. they have exhaust sound clips of all cat backs out there. along with everyone on the site owning them. did you want the magnapacks or the regular magnaflows? do you want balls out lould like nascar then get the slp cat back. magnaflow isnt much loulder than stock. both stainless steel. go to mx.com and listen to the clips and use the search button to find other questions like that (a lot of them). sorry for the long post just needed to get the info to u.
Magnaflows are pretty awesome and flow alot of air. I have 3 friends w/ magnaflows on there cars, 2 4.6's and 1 5.0 and they sound good on both. Im going to get some for myself next spring and get rid of my rustmasters.