@jrichker asked me to post what I found about 13" Cobra front brakes - If you go to rockauto(dot)com Select Ford, then 2003, mustang, 4.6l supercharged, brake/wheel hub, then caliper, it brings up their selection of calipers and hardware. AFTER CORE CHARGE, it appears as if the front calipers and hardware are ~$46 each/ side, and a set of front rotors and pads are $92. I'd also like to add that you can buy reman parts you know are in better condition than what you see on the classifieds for about the same price, I was looking into rear disc conversion and the prices aren't bad. You can also buy 5 lug conversion stuff for a little more, but you know it's in good shape. The ONLY thing I noticed about the Cobra parts is they don't say "COBRA" on the calipers. For me, I couldn't care less as long as the performance is there. Hope this helps, I know @madmike1157 uses the site, I've had good luck with them as well.