Is it hard to remove the heads with the manifolds attached?
Its not hard. Just make sure you take the midpipe down first, if not you will get bound up by the studs that bolt the midpipe to the manifolds. When the heads are coming up there will be a couple bolts that will stay in the head because they will not come all the way out. They are the ones by the strut tower. Just pull them up and wrap a rubber band around two studs and hold them together. Itll side load the studs to the bolt holes and keep them from falling down.
I would also recommend pulling the cams out before you remove the head, or at least remove the followers. With the cam and followers installed, it hangs a couple valves open and you dont want to risk bending valves if you bump the deck while fumbling with the heads. I would install the same way.