Well, this last week i got new brakes all around on my car. I put on the Cobra R (brembo 4 piston) 13 inchers on front, and did the Cobra rear upgrade (11.65 inch discs, stock calipers). I know there was some concern about going with bigger brakes and adding more unwanted wieght. Well I measured my new brakes before they went on and then measuered the stock GT brakes when they got pulled off. Measured on a digital weight scale. Here is the info: Stock GT front caliper: 10 lbs each Stock GT front disc : 15 lbs each Stock GT Rear disc : 10.2 lbs each I didnt measure the weight of the rear calipers because the cobra calipers are the same as the stock GT, just different colors, so i assumed they weigh the same. Brembo 4 piston front calipers (cobra R): 8.4 lbs each Brembo 13 inch slotted vented front discs: 18.6 lbs each Brembo 11.65 inch vented rear discs (cobra): 11.4 lbs each So the weight that you put on with this set up is about 6.4 lbs over the stock brakes. To me, that is a very negligible amount of weight for amazing stopping power and huge brakes.