Ready to start, calipers rebuilt and painted.

Done

Stock SRT and NA with 300mm disk.

Old and new!
here is info for the rear 300mm CLK500 caliper and vented disk. Easier than the front.
A set of 2005 CLK 500 rear calipers.
to rebuild Centric Caliper Kit 143.35022 (optional)
(4)Bolt Depot.com metric flanged (10.9 hardened) 10mm x 1.5 x 30mm bolts, stock bolts to short, do not get any longer than 30mm!
rear disk and pads,
https://www.buybrakes.com/mercedes-b...-kit-939-35502
i went vented and cross drilled.
also good time to go with SS brake lines!
Speed Bleeder SB8125L (2) Optional

jack up car, remove tire, disconnect brake line, it will drip. Remove caliper, then disk. Put on disk then caliper and pads. Hook up brake line and bleed. This is all bolt on, caliper clears the wheel fine, replace tire and drive, much easier than front, plan on a few hours.

Nice write up, short and concise.
It might be better if you stated this is for mod to an NA. Your old an new pic shows just the size difference, as it really shows an OEM and an SRT disk.

Correct, this was done to a 2005 NA coupe, along with the 345mm front mod.