I have the cd's thaey have complete part and diagram description along with technical info on every BMW I listed. You know when you go to the dealership and tell him you looking for a part and he pulls up the diagram with all the part numbers and how it assemled and points out "is this what you're looking for" . Well this is the exact same thing he looks at. Example i was looking for the rubber stripping that goes around the european bumper on a e30, it gave me all the pcs and illustrated how it was assembled.
the TIS (technical) cd allows you to put the model of your ca, you put in the symptoms you are experiening and it gives back causes and soltions to fixing it.
hope this outlines what the cd's do.