The rear cobra calipers are the same as the GT? So basically all that work is only for a spaced rotor that is .5" bigger?
The Cobra rotor is 11.65" in diameter and vented. The GT rotor is 10" and solid. The difference is really between the solid and vented rotor. The vented rotor will resist fade MUCH more than the solid rotor.
The M-2300-M kit is $175. That alone makes it worth it to me, plus when you do the fronts, it won't look out of place having puny rotors.
You will need to pull the rear axles to do the install however. It's pretty easy though
Chad's 2000 Mustang GT American Racer -- Cobra Rear Brakes
As for buyfordracing.com...yes, they customer service blows. However, i did buy my kit from them.
My calipers were brand new. They came in FORD boxes unopened and in FORD packaging. The rotors were
Brembo and the SS lines were new too. If they were reman calipers...there is nothing to indicate it.
Also, the GT MC and Cobra MC are the same. They both use a 1 1/16" MC on the 99+ GT. Mach1 and Cobra. The V6 uses a 1" bore, but it uses a vacuum booster. No need to change the MC. you just need to make sure you bleed the Master Cylinder bleeder screws on the side. Most of the time, it's needed. A lot of guys don't do it and the brakes are a little spongy.
I installed the Mach 1 kit on my GT and it would such your eyes out. I loved it. I left my stock GT brakes in the rear however.
I transfered the brakes to my Fox when i traded my GT in, but i did the Cobra rear brakes to match. Now with the cobra rears, and a car 300 pounds lighter..it REALLY sucks your eyes out!