Admin: Please move this post if it belongs in another forum like wheel/tire upgrades. I am contemplating an upgrade to my Fiesta ST's brake system. Mountune used to sell a brake caliper/rotor upgrade that saved about 8 lb pe axle. Has anyone done any research on weight savings from upgrading to slotted/aluminum hat rotors for our cars? I see that the big names (Stoptech, Brembo and Willwood) all offer brake line, rotor and caliper upgrades but has anyone actually compared the weight of the stock equipment to the upgraded equipment? Also, does anyone have any thoughts or experience with any of these kits? Seems like you couldn't go wrong with any of the big three: I have previous positive experience with the Stoptech slotted Aerorotors on a Viper (they were actually the OEM supplier for the last-gen Viper ACR (2008-2009). When I was at the Ford Octane Academy I noticed they upgraded all of the Fiestas and Focuses (Focii?) with Willwood calipers and of course Brembo is Brembo. Lastly, do certain kits not fit under the stock 17'' rims? I have a set of 17 x 7.5 Mountune Allegeritta rims that should fit most big brake kits but I have seen posts online about some of the above big brake kits not clearing the stock rims or needing a spacer. I have mounted winter tires on the stock 17'' rims and plan to swap them back on the car during the fall/winter. Thanks for any advice you can share.