Importing cars to Japan...any advice, tips?

[C-unit]

I know many of you are in the military and stationed in Japan so here are some question for you folks. I hope you guys can lead me to the right direction.

I am looking to import some euro cars into Japan. I've done some research and I know I need to do the inspection and emission but I couldn't find more info. Is there any modification require or better yet, is there any company in japan that will help with the import/registration process? What is the tax/duty like? I couldn't find much info on Japan custom website. Any help, lead would be appreciated.