The USDM headlights have two bulbs/sockets on the outermost corner, substantially bigger, and thus the mounting bracket to the inner fender is completely different. Also, if you use OEM USDM HID igniters (which mount on the bottom of the headlight), you need to remove the bumper cover to get the headlights in and out. Whereas the aftermarket igniters go in the engine bay and the headlight is slimmer and can be squeezed in/out with the bumper cover still in place.