I should imagine that you'd stuggle with a K11 as it'd foul on the dash supports and all the switches etc. That is if you're talking about a double DIN unit. If you're talking about fitting an actual JDM unit, I wouldn't bother, the FM radio band is narrower over there so you're likely to miss the top or the bottom of the range
my March has a double din, there is no problems if you have a facelift dash. but if you are after a JDM double din head unit then MicraFish is selling one!