Originally posted by Mint
The Specdb is the key according to that guy on the Xentax forum, this allows for limitless modding of all parts, you can probably select which tracks are shown and payable in game with the COURSE.dbt file?
Hello from "that guy"

I've never tried anything to add/remove courses into the game, except for having the moon circuits to show in the track selection. Didn't work out the way I imagined and I gave up quite early on that matter. It was easier to include the LRV into the PD Dealership.
Adding new tracks would mean to deal with some other files as well, from which I'm glad I can read them and pull data from them. This is
WAY beyond editing your savegame in a hex editor.
I've only ever looked at what PD have added/removed from course entries in the "specdb" in each patch. There were signs of a track short of releasing the Senna content (which would have fitted the Senna story). But it was pulled in the next update. Course data for this track was never included in the patches, just its name.
Originally posted by Mint
Is there a spec database file in the game install?
There is. It is double encrypted. Using flatz's tool will only remove the first layer, but there is another one. That's why (after removing the first layer), the db0105.dat and db0106.dat should show similar data at the top when looked at in a hex editor (IIRC, it's been quite a time when I was looking at it). As editing these files would allow the most awful crap, I've asked flatz to not make it public too.
The specdb btw. is very likely to be renewed in patches (as it must contain new cars and values for them). IIRC, there were two patches for GT6 where the specdb hasn't been altered.
Originally posted by Mint
contents of specdb
The specdb is sqlite3. I'm not looking at it the way you do