Foxwell NT520 does good testing on Benz W211.
Foxwell NT520 did EGR test, run simulated compression test and that alone might be worth the scanner price if you are buying used car (the simulation is not too accurate per several experiences, but beats pulling glow plugs)
Now since SBC come to the question here, I don’t have it on my W211, but here are screens that show when I enter my car system. How much it would show on SBC I don’t know.
Foxwell NT520 is a lot easier to throw in the trunk and not worry about compared to a full blown STAR clone with a laptop computer.