I really love the CD Rom, I highly recommend it. You get:
-the engine manual
-the chassis and body manual(two books in paperback)
-the maintenance manual
-the owners manual
-the climate control manual
-the electrical troubleshooting manual
If you purchased separate manuals, it could go over $300.00plus? dollars.
What is really nice is the paper manuals have barely an index, and the CD Rom leads you to what you want to find.
Plus, you can isolate just your year and model, instead of reading directions for every car.
Plus you get to take a break and come in the house...
The Chilton's manual for the '79-80 300SD is good for comparison and to take in the trunk. It covers every model from 1974-84. So there is not much focus on just our car like the CD Rom. I would have bought a CD eventually, but I got lucky.