US imported vehicles and Japanese JDM imported vehicles can both mount the aforementioned number plate sizes aswell as the smaller custom import number plates found in our number plate builder. The reason both US imported and JDM imported vehicles can’t use all of the generic imported size number plates is because there is no stipulation between the original location of imported vehicles outside of the EU.
However, American imported vehicles usually have a number plate recess to accommodate the 12’ x 6’ number plate, 303mm x 152mm, whereas a Japanese imported vehicle has a larger recess to mount the 13’ x 7’ number plate size but alot of JDM imported car owners, from experience, prefer the 13’ x 6.5’ imported number plate size as it is the best compromise out of the 3 generic sizes.
It is worth noting however, that you are not legally obliged to have the same size imported number plates on the front and rear of your imported vehicle. It is common to have different sizes on the front and rear. For instance, a Japanese imported Honda integra DC5 has a larger number plate recess on the rear of the car to accommodate a 13’ x 7’ number plate whereas the front number plate bracket is best suited for a 12’ x 6’ number plate. Both these sizes are road legal on an imported car.