I bought Spintech mufflers off Ebay, then went to the local Mustang place and got intermediates, and then I bought some Flowmaster tails (went overboard on the tailpipes because it was what wanted). Not sure if Spintech does catback, but piecing one together could be done for probably $300-350.
You dont want to get a full spintech catback. Its very expensive. But if you have to have one order it from their site. Otherwise do what everyone else does. Spintech mufflers and 3 inch flow tails. Just my two........
I purchased my dumps from spintech directly. Flow tubes, mufflers, hangers and dumps with shipping was $240. They were all welded up and ready to instal. Great product, superior quality.