The following is copied from the shop that I brought my copy of the game from in Australia..
"The Gran Turismo 6 Anniversary Edition Contains:
"The Gran Turismo 6 Anniversary Edition Contains:
- Gran Turismo 6 game
- Special Polyphony designed 15th Anniversary Steelbook
- And the following digital content
- 1 million in-game credits
- 20 cars with special 15th Anniversary custom livery and performance enhancement
- Custom paint chips, custom race suit, custom race helmet and custom avatars"