As the others stated, the screws on the foot treads can be a pain in the arse. I've found that squirting each one with a good penetrating oil twice a day for a week really helps out. Also the impact driver does work well. Shoot, you might get lucky and they'll come right out!
On my 800, I had to pull them and they came right out. The PO had put antiseize on the threads before putting them back in. Thanks Matt G.
