After much research, and considerable deliberation, I went with a Flowmaster cat back 40 series, SI/DO setup with 3 1/2 inch slash cut rolled edge tubes. It sounds great!
I know that alot of guys prefer the Magnaflow, but a bad experience with Magnaflow and a 302, '91 F-150 SI/SO left me with a lousy opinion.
So, to all concerned, Flowmaster and Ford really do sound good together (in my opinion).