It's really stinkin heavy too but I guess Mercedes doesn't care.
The late model S, CL, and SL AMG cars use twin slider calipers on a single mount. None of it is aluminum. I haven't weighed the stuff but it has to be much heavier than the aluminum 8 piston calipers.
The smaller AMG cars have all gone to 6 piston calipers, including the SLS.

The Bentley Continental GT uses a 405 mm front rotor. Yes, a 16" rotor. The brake caliper is a slider in a large mount. It dwarfs the 8 piston calipers Oz and I are playing with.
Bentley wanted the largest production brakes and they got it.
Going that far is taking the one-upmanship a wee bit too far. There's no need for anything that heavy on a sports car, even if it is a 5000+ lb Bentley.