http://home.hiwaay.net/~gbf/mbmodels.html
The W126 is among the very best lines that rolled off the Sindelfingen plant. It's hard to know from today's offering that MB used to care. The W126 design improved on some aspects of the W116 line that preceded it and gave up nothing in comfort, performance or reliability, unlike the wretched excess (and thank goodness for it

) that is the W140 line that superceded it. Short of buying an abused car, there should be no such problems with a W126. When you find a candidate that piques your interest, spend $150-200 for a proper prepurchase inspection. Discuss these specific concerns with the shop for peace of mind. For specifics, check the archives for what to look for when buying a 560SEL. Very commonly discussed on the forum.
Now, speak to JimF and get the perspective of someone who really likes his W140 coupe and has figured it out from end-to-end. It is a fine car in its own right.
Those AMG kits are long gone. Who would stock a kit for a 15-25 year old car? You might get lucky and find a NOS kit in the back of some warehouse but I wouldn't count on it.
Sixto
95 S420
87 300SDL