My 8/88 TE DOES have self-leveling suspension. I know that the TE has been made since 1986, but do not know when they first started having self-leveling. As for an FAQ site for pertinent 300E info, other than this one, I would suggest the MBZ club that I mentioned earlier in this thread.
Anthracite/Grey MB Tex
205/55/16, 16x7.5 Lorinser 15-hole
'95 S-500 corners
50% tint all windows