Valve Spring Compressor
The valve spring compressor I used is a K-D Model No. 2078 (Made in USA). I bought it about 10 years ago and I can't remember where, could have been NAPA or J.C. Whitney. I have seen similar ones at Pep Boy's for about $20 that should work just as well. The compressor looks like a hub puller and has two hooked arms for grabbing the spring coils. It is made specifically for removing valve springs with the head on.
A small magnetic retriever is also an essential tool for this job. You need it to grab out the small keepers from the top of the valve stem after compressing the spring. I also have a set of sharp picks that came in very handy for manipulating the keepers so I could grab them.
Note that on the M103 engines, there is plenty of working room around the valve springs. I saw pictures of other MB engines in repair manuals that have double valve springs or have the valve springs recessed in a well and I'm afraid the compresser probably won't work on those models.
The valve stem seals that I removed did not look as bad as I thought they would. They were still soft and the ridges that seal against the valve stem were worn slightly when compared to the new seals. The new seals I bought were brown and black. The old ones were all brown. Regardless of color, the intake and exhaust seals can be distingusihed by the hole size and by their shape. The exhaust seals have more of a domed top.
I have not noticed any oil loss yet but have only driven the car a couple hundred miles since the work.