Hi mate , heres an old post of mine , hope it helps !!!I
recently got some custom plates for my R32 GTR , i tried bending the old bracket to fit this did not work , also didnt want to bend the ends or cut the ends of thenumber plate off to fit on the front as this looks untidy , i have limited mechanical knowledge and time but this is what i came up with !
Got some zenith 100 x 100, 90 degree steel brackets from bunnings hardware :Dand drilled new holes in them , so the plate would fit flush to the front bar using the three existing mounting screws .
Cut some pieces of 2mm powdercoated plate the same size as the front plate and the rear plate with a grinder. Rivetted the 2mm plate to the brackets for strength and drill holes to mount plates in corners
Remove front bracket again (undo underside screws) , paint both steel plates , Do the same job with the rear but use existing mounting bolt holes as fixing points for big rivets (works great ) drill two new holes on the bottom of rear bracket depending on what size plate you have, i went for square rear , slim front .
Finally rivet custom plate onto steel backing plates to make them harder to thieve ! paint rivets black to make good !