Yes. I think I'm in way over my head too.I think a genuine c18 copy would surface before the job was done anyway, and the problems of sorting out the interactions between the various files and particularly of how they are utilised by the differing fw and the os i reckon would be a major stumbling block as i'm sure you know. Reverse-engineering is a younger man's game .....
I was hoping that because the timestamp on the C2 map file is a year later than that on C1(V17) it could be the genuine 2012 version and only needed moving into the older working DVD.
However, I have just dived into my archives to see what changed in the V16 to V17 upgrade last year. Unfortunately, I found that a lot of the other files changed too. Even allowing that some will be just additions/amendments to POIs or business phone numbers there are far too many unknowns to be confident of success.
I have found some manuals on .kwi files, so I have something to read while we wait for V18 to appear somewhere.