Havent really looked into it on the i 30 ,
but do you need to remove the bumper???,
The whole time i was working with installing car electronics we never took a bumper off to install these little buggars,
Easieiest way measure then using masking tape run that accross frm left to right then measure and mark with a pen/pencil on the masking tape stand back and check visually (in case of wrong measurements and aspect) Then use a drill hole saw, Drill holes poke wires through and pick them up from the boot or through the tail light areainside the car, wires allready run to number plate lights,
Good luck ,
Steve