ard said:
Why wouldn't you just buy the M5 pads for your M5??
If you're going to buy OE pads, then by all means, buy the ones intended for the M5.
If, on the other hand, you're going with an aftermarket option, then it is important to know that the M5 pad
shape (and most importantly the pad's backing plate) is the same as the E38 7er and X5's and 8ers...
When going by the ETK alone, it can get really confusing b/c BMW uses different pad compounds (and therefore different p/n's) for the different applications.
If you decide you want to go with Mintex Red Box or Axxis Deluxe Plus for their low-dust for same friction performance properties, then knowing your pads are the "same" as a 7er or X5 will help. Those vehicles are far more prevalent than the E39 M5, so cross-referencing is more likely to make sense using those models.
Back in the early days of E39 M5 ownership, you wouldn't believe how difficult it was to find out who made an aftermarket rear pad for our beloved Beasties. That may have been the very issue that allowed Google to lead me to this forum--an oasis of information (and vortex for discretionary funds)--every day since!!
-Dave