96 E320 repair manual
 

I'd like to get a repair/service manual or CD but not sure which would be the best place or type to get.

There is only one choice that makes any sense.

1-800-FOR-MERC and ask for P-2700-210-05. It costs $150 plus tax and shipping. It's a DVD.

Unfortunately, it does not cover the internals of the 722.4 transmission, so if you want to rebuild your automatic transmission you will need another manual. But it covers the rest of the car (and does have full information on rebuilding the 722.6 transmission used in MY 97 and on).