The only problem I had was taking out the rotor retaining screw. It wouldn't budge, and I even started stripping the head of the screw. An impact driver solved this. I reccomend one. To get to the screw, just remove the cap and turn the key a couple of times until the retaining screw is visible.

The NGK plugs will probably be really close if not perfect for the correct gap. If they are out, it's not hard to gap them. The auto parts store you get your plugs from would probably gap them for you for free if you ask.