Holy crap that kit is outrageous. You can buy 14" Brembo brakes for cheaper than that.
The question was: "will gt500 calipers fit 03/04 cobra rotors?"
GT500 14" rotors are obviously larger diameter than Cobra 13" rotors and they are thicker. So no, they don't just bolt on.:nonono:
The Vintage Venom 14" kit is an awesome value. The rotors are fairly cheap to replace and they reject so much more heat than the 13" ones, even the pads last longer. Obviously they also provide a significant improvement in brake torque.(leverage advantage from diameter)
If I knew then, what I know now, I never would have spent the money on my Focus RS 4 piston Brembo calipers.
If you are a "tracker type" you probably already know that for the weight and speed capabilities of a Terminator, our 13" rotors are not able to expel enough heat once you get even semi fast. They crack fairly quickly unless you run NASCAR brake fans in your cooling ducts.(c/o racebroncoII)
2000 Cobra Rs and 03/04 Cobras IMHO should have been built with 14" GT500(Brembo 14") brakes right from the start.
The 13" 4 piston Brembos should have been on the 95 Rs.
If you are not a hard core tracker type the 13" 4 piston Brembos are still an excellent brake package and it does resolve the troublesome pad tapper issue and caliper spread issue from the two piston PBRs, if you are a less than hard core tracker type.
There's that "sick" word again...:shrug:
I guess you mean they are nice, awesome, fantastic, etc., etc.?
Sorry for the miss use of the english language. The Venom 14" brake kit is the most fabulous brakes I have experienced on a mustang my entire life.:-D