マイペース、マイ・スタイル！　～日本語がぺらぺらになるには～

I'd say 親日家. I've heard 日本通 too, but as far as I can guess that means purely "knowlegdeable about Japan"sethg: 日本贔屓 means something like, preferring Japan, especially over other countries.(日本かぶれ）