Not to sound like an Asshole but why don't you search ? The Bassani X pipe has got to be the most popular X pipe for Mustangs. A simple search on internet would help you .
I have full Bassani from the headers back with H/F Cats, its a very sexy sound although whenever I get the Registration switched from Cali to Ga I plan on getting the O/R version. Right now its not quite loud enough for me.