Following 16yrs ownership of a G60 I've now bought a Merc and have been looking through the Merc forums, where there are references to free , no-registration manuals on the web. In all the time I've been lurking on the Corrado forums I've never seen this Russian site mentioned as a source of info.
http://www.detali.ru/cat/au/au.dll?SelM ... ljYxv5aAe4
(go to the bottom of the page and you'll find 1989 - 1995 all link to English tables of contents, e.g. the '91 - in English is
http://www.detali.ru/cat/au/au.dll?SelG ... j_eHueUQ==
...and that's just for Corrados.
Start at the home page, http://www.detali.ru , and you'll find links to loads of assembly drawings and bills of material for many makes of car.
If you don't already know of it I hope you find it of use.
Meanwhile, I just can't bring myself to sell the faithful G60 !