I have a cls 55 amg that I bought three years ago and I need font brakes and rotors on it now. There aredifferent rotors for this model if it has the performance package and the rators are like $1200.00 a piece. Compared to $140.00 apiece for regular amg perforated rotors. My question is how do I now if my cls has the performance package? Someone said I can tell by the vin number. Any ideas.