Go to www.perfectmarketaudio.com scroll to the bottom of the page under "LINKS," find the link "Mercedes Radio Plug Diagram."

The original radio in your W140 had built in amps also (25-35 wpc) so fitting another radio with amps should be ok as long as they're not TOO big. You didn't say what year yours is so be aware that the '91-'93 cars had those two-piece radios that are a bear to replace.

Good luck.

Ray