Everyone says you need a torsion key removal tool but a large C-Clamp works the same. If you are super worried, rent one from you local auto part store. It's a refundable deposit.
As for difficulty, we had to use an air hammer to knock my torsion bar out of the pocket in the LCA once the keys were out because it was in there good. Other than that, it's an easy remove and replace that can be done with basic hand tools in a few hours in your garage or driveway. There are even a couple how-tos floating around on doing the rear springs and there might even be one for the keys.