Emmy,
It is a DIY affair if you have nice metric flare wrenches and jack stands:

http://db.mercedes.cx/sec/199908/0101.html

Instructions for the other things I mentioned can be found by searching through the mbcoupes archive, as the C126 shares most components:

http://www.mercedes.cx/560SEC/archives/secq.html

Cheers, Andrew Seidel.

__________________
86 560SEC
85 500SEC Lorinser
83 300D Turbo
75 240D