On any other High performance car like the Merc or the Audi you get 6 Piston calipers. And some cool air in the wheel arch. Then they don't fail!
Don't act like the BMW M3 brakes are just fine and perform well!
I have witnessed many stock cars with 6 pistons calpers that have had brake problems just like you had.Their drivers also overused the brakes to what they were designed to handle.The only stock cars that can brake at 100% capabilities every corner,every lap are Porsches with the ceramic brake option and they are a $12000 option over an already great brake system.