The Cobra R brakes are 4 piston Brembo calipers vs the Cobra PBR 2 piston calipers. They are better, but only if you are really taking the brakes to the limit. For daily driving or spirited occasional track duty...the Cobra PRB calipers are fine. They use the same 13" rotors. If you do a LOT of autox, then the Cobra R calipers might be worth the extra few hundred....but, if it was me....I would just stick with the Cobra PBR calipers.