I just replaced the mounts on my 82 300D a couple of weeks ago. I used the octagonal mounts from Phil and also did the following modification to help deal with the vibration:

http://mbca.cartama.net/showpost.php?p=89120&postcount=3

Get the heat shield cups for the new mounts if you don’t already have them (mine didn’t).

I also replaced the seal ring where the U-boot attaches to the air cleaner housing. The old one was so badly deteriorated that it wasn’t immediately clear that the ring first fits over the outlet and lip on the air cleaner housing (NOT easy—do this with the air cleaner out of the car), and then the U-boot fits over the ring. It takes some effort to get it all into place while aligning the housing with the mount bolts and oil drain pipe.

My air cleaner bracket looked OK, so I didn't have to bother with it. This time.

Good luck.

Charlie

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05 E320 CDI - 175K miles
82 300D - 200K miles (sold)