[Dobervol]

...and my search fu is weak, because this has to be an easy question to answer, but I've given up after about 2 hours of searching.

How do I know if I have the high speed rotors? I have a 2011 (late 2010 build date) 535i manual 6, supposedly with sport package but NOT M-Sport. I have no idea whether this just means a different wheel and tire package, or has anything different in the way of suspension or brakes. I bought it from a BMW dealer with only 2k mi. on it, but no window sticker.

It's been under warranty until now, and this will be my first brake install not under warranty, so I'm going OEM, but having a local guy do it.

I have the 19" wheels with the 275/245 stagger. The only difference from what I can see btwn high speed and regular rotors is the width, not diameter, of the rotors, but since mine have 50k miles on them, can I just take a micrometer side to side and tell which it is, or will the wear numbers throw it off?

Apologies for my stupidity, but if there's an easy way to tell, I'd sure appreciate the help.

[zugellos]

The fail safe way is to remove the tire. Then simply take a look at the rotors' outward facing surface. I recall the manufacturer part number can be seen etched/stamped into the metal. Then just order the same part.