This would be a deal killer for me.

No matter how good the JDM ones look while parked, I want the best light pattern I can get when I'm driving at night. On US roads where we drive on the right, that won't be the JDM pattern.

 

I use FedEx all the time for international shipments. It can be rather detailed getting all the information both countries require. (non-commercial goods in this case) I can't think of anything with the lights that would be a dangerous good.

That being said, these kinds of shippments are easy to track. You know where they are and if there are hassles with customs. You will spend at least $100 getting these to Japan. Make sure you go for "next day" delivery. You might think that will be more expensive but if you opt for the second day, you have to pay for the extra day parking in customs and that can double shipping charges. It is not like domestic shipping.

I would think other shipping would have good tracking too. Good luck. The only JDM thing I went for was the left hand convex mirror. Love it.