Fitear are eccentric. To buy one of their IEMs, you have to fill out an application form, provide photo ID, and provide proof of residence : some utility bills or something that confirm the name and address. Then you are entitled to join their waiting list. I don`t know if this is only for foreigners or if Japanesse also have to do this. Currently the only universal Fitear that you can buy is the Parterre, and it`s very rare. The 334 and the `Fitear` model you have to apply and wait.
Regarding Jet in Bangkok, I can second Chodi that they are good people, and there are at least two fluent English speakers there (basically none in Japan). However, the prices of most audio gear in Bangkok are much much higher than in Tokyo.