I can't really speak about buyfordracing.com
I get everything from ether summitracing or Jegs. If there is every any problems they make it right no questions asked.
I'm real happy with my FRPP 3:73's. I've had them installed for about 4 years now and have had no problems.
If you are an Auto, then i would suggest 4.10s not 3.73s. Most guys on here will tell you nothing lower than 4.10s for Automatics. For manuals, that's another story.... The debate on 3.73 vs 4.10 may never be decided lol.
i hate my 373s they absolutely killed the top speed of my car and these cars have way to much of an overdrive in fifth so its like hitting a brick wall when you hit fifth