The pronto rotors seem like a great option. I will probably get them when the time comes to replace my rotors.
However, if you are thinking about spending the money on the ECS rotors, I would consider the RB lightweight rotors as well. 5lbs lighter than stock. I believe you have to purchase the pads from them as well though as the do a minor modification to them.
My friend is running their lightweight front and rear rotors. They are very high quality. We have literally beat the crap out of them through local canyon roads and they didn't miss a beat while with stock rotors/pads he was getting brake fade. I forgot what pads he got but if you decide to considering them as an option let me know and I will find out/get you more feedback.
Front:
http://www.racingbrake.com/135i-E82-...-11-p/2166.htm
Rear:
http://www.racingbrake.com/Two-piece...008-p/2167.htm