I believe phillips makes an HID kit for xenons. I don't know if the headlight assemblies on the ML for xenon are different than for regular lights..
Try searching for Xenon using the search feature found near the top of the page on the right.
'92 300CE - Sold
2004 C240 - C7 Wheels
2015 ML350 - P1, Pano, Ash poplar wood, Sport Dinamica interior, Running Boards Keyless go.