I had to make the hole larger, the instructions said that on the 94+ that the hole was actually smaller than the fox holes. I just cut a relief in each corner and bent that section back then after the boxes were in I bent them back to were they were stock, I plan on welding them back together or making a plate to cover the area someday.
Also be aware you have to re-locate the ABS brake line/or E-brake cable (cant remember which one it is, I drilled a new hole just off to the side of were the top plate bolted to, undid the cable and put it down that new hole out of the way.