Owen, if u want to show off some jap heritage ... u should go for hiragana or katagana instead of kanji. Cos kanji is just chinese. If you put those letters on your car, it will give more of an impression you are chinese or showing chinese heritage, doesnt give much japanese "feel". If you ask me, with kanji, it will look a bit like cars in china, cos often the car makers put kanji characters on the domestic cars :-).
just my 2 cents....