most applications are stricktly for sound. aparently the exhaust sytems that come with the trucks is very good. i'd just get the catback, and forget the xpipe, might not sound as good as you think. mustangs sound great, but for some reason i've never thought that a full exhaust lightning sounds that great.......i'm too afraid it'll sound like a log truck, or a z71....lol
just do a search on various websites for soundclips, etc. and choose what you like best. for me i got the inexpensive MAC catback. of corse the tips have rust b/t them, but i can replace those with a nicer pair at any time, and it sounds great.