A while ago I posted that I was about to fit new brakes to the X350 and had chosen Mtec grooved and coated discs, more because I liked the idea of the coating so the non friction areas do not rust, I have fitted these and are now in discussion with Mtec as the combination of disc and pad is very noisy and lots of vibrations are transmitted during certain braking situations (well most) worst at speed with light pedal effort.
I'm not sure why, neither is Mtec (although they appear to have stopped talking) I have ordered some standard discs and will be returning the offending items for a refund (hopefully). Anyone else had issues with grooved discs? I expected a bit of noise but not the severe vibrations, I do not believe it is due to excessive run out or uneven pad material transfer on the disc.

 

can't help ya there, bu I assume you are installing new brake pads with the new rotors?

 

I have no idea what kind of coating would work on disks unless it is just on the non-contact areas. Using drilled or slotted rotors on street cars can be frustrating. They offer no increased performance and in order to brake properly with the decreased surface area, they need higher performance pads which can be squealers unless fully heated by heavy use. I stick with OEM brakes. If you do anything, use top quality pads such as Hawk HPE. These are high performance ceramic and the best I have tried. As far as why the brakes are vibrating, the pads are either loose in the caliper, the caliper is loose or has worn guide pins, rotors are out of balance or the pads are not working right.