jimh6

Forgive me if I overlooked it but trying to find information on replacement pads and they suppose rotors although I'm not opposed to OE for the 2018 E400 4matic.
Really don't want OE pads. Probably coming down to EBC, Hawk, or Akebono. (in that order of preference)
After looking around online, I found very little for this specific car. And I do believe they're different brakes than the E300 which has plenty of options.
I did however, find parts for a 2019 E450. Same size?

NorseWagon

The E-450 Wagon has 14,2 “ rotors front and back, with the front ones cross drilled.
Don’t know what the E-400 has, guessing the same..

cetialpha5

You need to get a copy of EPC to verify the part number but on FCPEuro's site, the aftermarket option is Bremo which is more than the Mercedes part. And yeah, that sounds like Mercedes, different set of brakes for each line, probably different for the AMG also. And more expensive. If the rotors aren't bad, you could do a pad slap which is just to throw on a new set of pads without changing the rotors. You can just measure them with a caliper, lots of times they just like to change out the rotors without the rotors actually being too thin. You could have them turned too, but in this day and age, probably not too many places around that still do that unless there's a machine shop near you.

2012 merc amg

I'm not totally sure they make them for the E 400's but I put power stop Z23's on my S 560 and the pads and 4 rotors were 1000.00 on Rock auto. Great brakes. No noise, smooth stops and better performance than stock plus the real good thing is being Ceramic pads no more brake dust on the wheels.