I don't know but I'd pay that much if I were sure it would be done correctly. I've done clutches on numerous vehicles, Mustangs included, and I'm getting too old to do it in my driveway.
I've done 74 340 Dart sport, 69 GTO, 85 Toyota 4wd, 80 Audi 4000, 89 5.0 LX. As I recall the biggest PITA...