Lonely_Dolphin on 20 June 2014
Confirmed by Nintendo of America via Twitter (link below), Japan isn't the only one getting this free DLC this Summer! Hopefully the rest of the world will be able to get their hands on it aswell!
http://twitter.com/NintendoAmerica/status/480017305502773248
So now the question is, will you use it!? I most certainly will, once I re-get the hang of outside drifting anyway! 
EDIT: Just checked and it's confirmed for Europe too!
https://mobile.twitter.com/NintendoEurope/status/480017684118380544/photo/1
