Read in the MB archives website that US W124's carry thicker spring pads than European ones (8-13-18-23mm) due to headlight specifications.
Can someone confirm this
If so, what part numbers do these thicker US-pads have?

Cheers!

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2011 Prius

I think what they meant was US models use thicker pads then european models when they leave the factory. The pads are the same, but what mercedes chooses to install before shipping is different. Here are the part numbers for a W124.

FRONT
201 321 09 84 (8mm)
201 321 10 84 - 13mm
201 321 11 84 - 18mm
201 321 12 84 - 23mm
REAR
201 325 09 44 (8mm)
201 325 10 44 (13mm
201 325 11 44 (18mm)

You can check the pads you have by looking at your spring pads and reading the tiny knobs on them. Check out the following thread.

Replacing rear spring pads...