Sony Computer Entertainment Japan and Asia is holding a promotion that lets you grab a free code to download a Megane Trophy V6 15th Anniversary Edition for Gran Turismo 6 by using Twitter or Facebook.
It’s worth mentioning that the code has to be used in a Japanese PSN account, but in Gran Turismo 5 most promotional cars actually work as long as the files are downloaded on your PS3, even if you aren’t using the account you unlocked the code with. It’s very likely that it’ll still be the case this time around and it’s free anyway, so trying costs nothing. If you don’t have a Japanese PSN account you can follow this guide on Kotaku to get one. It’s very useful to have one anyway.
Again, there’s no guarantee it’ll work on your European or North American copy of the game, but there’s also no real reason to believe that it won’t considering the precedents. Unfortunately there’s no way to know until the game will be released.
Keep in mind that the same car is already included in the GameStop preorder bonuses, so if you intend to preorder your copy there, you don’t really need to do this.
In order to get your code, first of all go to this url and scroll down to the middle of the page, then follow the instructions in the pictures below. The process for using Twitter is slightly different, but it’s easy to do anyway.