I believe the Yoshis and Shy Guys will be part of the Mercedes patch, and then accessible for use when you purchase both DLC. That way, even if you didn't purchase the DLC, you won't be limited to which races to join. For the tracks, karts, and other characters, I don't know. Perhaps they'll do they're doing with the Yoshis and Shy Guys. Put the characters and karts in patches to be released as each of those DLC gets released, and then just limit it by the tracks. Then again, that would make the idea that 8 tracks would be the 1GB and not the tracks, karts and characters together.