Unless you can be absolutely positive that the "rebuilder" has significant experience with M/B diesel heads, I'd strongly advise against taking a flyer on a "good machine shop".

There's many stories on this forum of folks who went that way and, in the end, the job was not correct and the head had to be removed due to oil consumption issues.

If you want a guarantee that the job is done correctly, ship the head to Metric Motors. Figure that the shipping cost of $120 ensures that you don't do the job twice. It's worth it.

http://www.mercedesengines.net/