I Would recommend a bassani x-pipe and a magnaflow catback exhaust.
WWW.stangnet.com is a good site to find parts on your moms mustang and they also have parts reviews.
www.corral.net is also a good site. Stay from bigger mafs they don't help. If you want to hear a clip Of my buddies 01 GT go to
www.family.com username: cegceg password:contour and look under utah cegs movies and find flyby and burnout by 01 GT. IT has an x-pipe and flows.