Watch out
I recently replaced my speakers and headunit in my 2002 4Runner, and I made some mistakes that I wouldn't want anyone to repeat. Be careful when removing the closest clip to the dash, it needs to be lifted up, then pried off. The armrest has a couple hidden screws in it, and the tweeter cover does not need to be removed and shouldn't be, since it's a very risky clip to remove, that's extremely easy to break.
Good luck!