I'm not sure on your reading comprehension because I'm just about to order an EFR turbo which is about the biggest single mod you can do to a Fiesta ST. My ST doesn't have any moon roof either. I was considering a Wilwood brake upgrade but looking at the various kits from Wilwood and TCE, none of the options seem appropriate. My solution: roll my own kit with FNSLR calipers and nice pillar vane rotors from another source. Unfortunately I'm a bit slowed down because the wheel situation sucks and I need about $8,000 to get a run of one piece forged wheels made and I want everything to work together instead of having $8,000 in useless wheels so it may take a while. I really hope I can get something together by the spring but its hard developing parts on your daily driver. As for the lightest ST around, my intention is to save weight with light wheels, light brakes (slightly heavier than yours), light exhaust, a lithium battery, removing trunk junk, trimming brackets and possibly replacing some steel parts with aluminum. There will always be someone who guts the interior and has a lighter car but I will be really happy if I can get close to 2,500 lbs. Not as easy as ordering parts out of a catalog since I'll be making a lot of them (yeah, I can do more than just drill rotors). Food for thought: Most drive trains have about a 15% parasitic loss, FWD is probably less because the final drive is a helical cut spur gear instead of a hypoid bevel gear. That seems to agree with the 197 HP rating of the 1.6 EcoBoost and low 170s whp dyno results (roughly 12.5% loss). If you were to neglect friction and brake rotors could cause a 15 HP loss, that would mean they were responsible for 60% of the parasitic loss and those big wheels hanging off the rotors account for no more than 40%. That would mean the moment of inertia of the brake rotor would have to be greater than the moment of the wheel and tire and to eliminate that 15 HP loss you would have to replace the stock rotor with a replacement that weighs 0. Wilwood rotors don't weigh zero and the stock rotors do not have a moment of inertia higher than a wheel and tire. Where does this mythical unmeasurable 15 HP come from? Stickers? For those that don't know, beside friction, the cause for parasitic drive train loss is the amount of energy required to accelerate the mass of the drive train including the clutch (I think), transmission, drive shafts, hubs, brake rotors, wheels and tires. I don't expect my light wheels, light tires and light brakes to have an effect that is anything close to even 10 HP but they should be good for handling as long as the tire compound and construction are good.