Just did this job this weekend. I'd been putting it off for a while, but it really wasn't as bad as I expected. Took less than 30 mnutes to get the tube disconnected where I could run a bicycle cable through it. Never did get it to go all the way through, but I was able to get it at least a foot into both ends. I believe all the blockage in mine was really limited to the first inch on the intake manifold side. It was necked down to practically nothing right at the intake manifold.
Get at the intake side bolts from the bottom. 10mm gear wrench worked great. The only other partially hidden screw is the backet back behind and below the oil filter housing. This is a 5mm allen, if I remember right.
I went ahead and removed the EGR valve completely, and tested it with a Mityvac, but I didn't really see any gunk here at all.
I purchased my car from a Mercedes dealer mechanic, who said he had just replaced the EGR tube at 80K miles when I bought it. Now has 141K miles. At this rate, I'll have to do it again @ 200K
Gary
1995 E320