Huge thanks for this post, got the job done on my 300D in about an hour. The instructions could not have been more accurate. I no longer have to pop the hood in parking lots to shut the car down, which i can't say i will miss having to do.

I ordered the "vacuum box, injector pump" from my local dealer (A 00 070 46 53). It appears to be the same as the plastic Bosch one, complete with the Bosch logo on it and the MB part numbers. It does require a bit more vacuum line that the stock metal one did since the hookup is on the top.