Only go for M model brakes if u have lotsa spare cash...calipers, pads and rotors alone will set you back as much as a high performance 4 pot maybe even 6 pot Brembo system bro......
E.g. my E36 front rotors cost around 2.8k a pair.......I could have replaced my E38 all 4 discs (ori), change pads (ori) and still have some spare change for happy ending massage....