Back when I initially wrote the decryptor, I tried to find the same data as well. I was expecting to see the usual SET format used for other object placement, since the DLC had the ability to place objects and SET entries are pretty easy to recognize on their own, but I didn't see anything like that in any of the files. I also confirmed at that time there is no SH4 assembly code in any of the downloads, so it seems that all logic in the downloads just comes from pre-defined features that the downloads can use. I still think there's got to be some equivalent of SET data in there, since the location of things probably wouldn't have all been defined ahead of time. The other odd thing is the lack of a reference to SSRACING.ADX in the file. In the SA2 downloads, once those were decompressed you could easily find the filename of the custom music track for Kart race downloads and even change it, but here there's no sign of it. Even if it were PRS compressed, text usually doesn't compress well in PRS and you'd still see part of RACING since the characters don't repeat. At some point this may make me want to look at the data again and see if I can figure out some of the unknown regions. Maybe in addition to encrypting the entire file, perhaps some sections were compressed as well. I don't think there's any additional encryption though, the data isn't random enough. I may have posted some of this information before, I just can't remember at this point if I did or not.