I did not have to take off bumper just used tape in the areas that the factory hardware matched up to splitter and pushed up on splitter to put the bolt marks in tape then drilled holes in splitter then installed with the factory hardware it was a pain used pillows to hold up splitter to make install easier and I used the support rods used a small screws to mount the rods to the bumper and regular hardware to mount to splitter
good luck not easy but the look is worth the work
