Welcome - From looking at you NAPA links I noticed that it did not show front calipers for the 2003 Cobra's. I'm pretty sure most people doing the conversion are using those calipers. I will be using 2004(same thing). Are the 99 Cobra calipers the same? I don't know. They appear to be differ by looking in the pics on the site. Will they work maybe - they also use a 13" rotor - so I can't see why not.