The last Metric diesel engine (240D) ate itself in about 12,000 miles :-/ Also had one of their 'full euro' 5.6L M117's in.. Had full custom headers, extrude honed intake, MSD ignition.. Made 235RWHP
My advise be Very careful in which machine shop you use....Only deal with one that handles Mercedes heads w/ utter regularity. Not the "yea, we dun a few"....
I go through the trouble of sending all my machining to New York from Atlanta just because I know the fellow does the job Right.
Jonathan