While you are in osaka..... why don't you visit
RC Champs ??
Tips : Buy RC World magazine ( japanese ) or American RC magazines, read the articles, prepare what you want to buy. It's good idea to write down the address of RC champ store in Osaka,.... If I'm not mistaken, the place is near ebisubashisuji shopping arcade.
Rc champ do mail order too.
Happy shopping.