1M has PS2 and M135 has PSS...
My 2011 M3 came with PS2 and now it has PSS. Believe me, The gap between those tires is really amazing. BTW the M135 is quick despit it's an ugly car.
2011 BMW M3 Coupe ZCP | Akrapovic Slip-On | M Performance Sport Pads
2013 BMW X1 xDrive 18d | ESS VT-650
Gone but not forgotten: BMW Z4M Coupe | Porsche 968 | Porsche 944 |