I love my Mac H with Mac Pro dumps. Good idle, sounds good through the RPM range, and you don't have the interior drone like flowmasters.

I rented the GT-H when I was in the states and that has the Ford racing exhaust and the sound was great.

stay away from flowmaster. mac in my opinion sounds sick on a stang. i love it. i had it on my mod cobra. longtubes, off road h pipe, and catback from mac sounds siiiiiiick and doesnt break the bank! good luck!

+1 for mac pro dumps too!