Installed my Curt hitch today.
I removed the mufflers and heat shields. This made the install much easier because of the 3.6's dual mufflers which would be hard to maneuvers the hitch around. Then I took apart the trunk and enlarged an existing hole on each frame rail with a step bit. It was only sheet metal so that went very smoothly. I fished the first bolt through and used my jack to lift the hitch onto them. I bolted it up and used the hitch frame holes as a guide to the drill holes for the 2nd bolts. Drilling into the frame was fine but take your time and wear gloves because there will be hot metal shavings dropping on your hands. I torqued them to spec and assembled the car.
If you enjoy doing this sort of thing it's worth installing it yourself to save the money. If you're nervous about doing it, I would pay someone to install it.