I'm pretty experienced with engine work, and swapping motors. But i would have to agree, doing a tune up (wires, cap, and spark plugs) is a !Removed! on 2jz's. The problem i had was dropping nuts into the dark abyss (caught on something and would not drop to the floor). Plus, the gaskets for the egr went bye bye. Anyways, It would be pretty damn easy if the engine was out of the car.
I think paying a mechanic to deal with it is a better idea. You could spend those hours working overtime or with your family, wife.
After you do it for the first time though, you'll be an expert. Be forewarned, it's !Removed!.
A flexible magnetic extension should help. Brake cleaner helps to clean the surfaces of the throttle body. Gaskets to replace the old ones, if you want, for the egr and throttle body. Toyota dealers don't carry them readily. Lexus ones do.
GOOD LUCK