i thought that this little bar was the only difference?cobra rear calipers are the same size but thicker, if you have gt calipers it wont fit cause the calipers wont compress enough. gt calipers are solid, cobra calipers have a vented center. if you have cobra brakes with gt rotors it will work just have to change the pads early. i dont suggest you mix and match
do you have a pic or a link to what you mean?