[Cammy5]

I went through this same process of figuring out how I wanted to upgrade the crappy standard M Sport 328i brakes (not the blue M-brakes that were a factory option). I settled on the M Performance Big Brake Kit which comes with 4 piston Brembo/370mm/slotted and dimpled rotors fronts and 2 piston Brembo/345mm/slotted and dimpled rotors rears. The improvement in high-performance driving/mountain driving (I drive the Tail of the Dragon at least once a year) cannot be overstated. They are pretty pricey retail but I was able to get employee pricing at the dealership and some of our vendors sell them for about the same - the yellow BBK was around $1250 employee price and the rear rotors (inexplicably sold separately) were around $450 or so I think. Don't forget, when you modify the braking system, you'll need to have the car coded for the new rotor size as otherwise, you deal with a mushy pedal.