I agree that Bentley is the premier D-I-Y'er reference manual for 240's. And Bosch's little blue books (which get fatter with every edition, like myself :-) continues through all its editions to satisfy my engineering interests.

One word of caution, though: check the archives on this forum for lists of errors that have been found in Bentley. A few can actually get you in trouble.

I just can't get excited about Haynes (or Chilton), though, because its prose always seems so generic -- I'm suspicious that it writes almost the exact same text for every car -- and its pictures always seem like they're of parts in the 1970's or early '80's models, despite the year coverage claimed on the cover.