for both the front and back plates i am using my american stick-on bracket.
then i screw in the korean GUARD that you get at your gu-cheong when you register the car. that is what directly holds your plate. as luck would have it, it has *good enough* screw hold placement to fit on the upper screw holes of the american bracket. whew.
i am not using the drill-in korean brackets or whatever. just the korean guard holding the plate and the american bracket.
the rear one has no problems. The front one however, you will notice, trips the front collision detector at slow speeds due to how far the plate sticks out in the front and on the sides (korean plates are long). You'll also notice that other model 3s in korea *curve* their plates ever so slightly in the front, if you look around. i asked around. it's to deal with that tripping of the detector...i guess tesla didnt foresee korea plates being so long. so even if their plates stick out less since theyre drilling directy onto the bumper, the length of the plate still trips up the detector, so they have to bend the plates slightly. go look around at all the model 3s (its unique to them) in korea. you'll notice that they (and i think maybe some other cars) have a bend in the plates to counter the length issue and tripping up the sensors.
so HOW did i bend my guard and my plate? well the plate is like aluminum. it bends easily. for the guard? use a hairdryer or a hot air gun of some sort, and carefully but strongly bend at a sharp angle as applying heat to the right two locations on the guard. easy peasy. Then it will not trip your detctors. your front plate will be slightly more curved than the koreans but its not too noticeable and importantly is still legible and not illegal.