I installed a CURT in the fall last year. We took the bumper off just because it gave us more room to work and it's just a bunch of screws holding it on. Your going to use at least one new bit to drill the holes. Its worth it to buy the more expensive one that is made to drill through steel (I forget what this one is made out of). They should have a chart on the wall at the hardware store. We ended up buying some longer bolts and locking nuts because we didn't want to deal with fishing the bolts through the frame. So instead of drilling 4 holes, we drilled 8 (top and bottom of frame). I can take some pics if this doesn't make sense. I don't use my hitch for towing though. Only for a hitch hauler (hunting and bicycles).