Though it was all done within about a week or so, I actually had the headers and cats installed first. Nice bump up in sound, but biggest audio step-up was the 'Gundo hack'. I got my Gundo mufflers from here: http://www.fdmotorsports.net/index_files/Page732.htm and had them cermachrome coated. Definitely louder, but not obnoxious at all (to me).