join a local mustang group and have a club member do the install...doing that i was only charged $100...had to help him hold stuff but I learned a lot.
i got my whole rearend rebuilt and 3.73 gears and trac lok for 800...the place where i got mine done was 45 minutes away from you in NJ...its actually the town over from me and they specialize in mustangs. Send me a PM if you want to know more.