Because your 4runner already has a V6 in it, the engine itself is more or less a "plug&play" install. You will have to do some wiring work, and exhaust work. But the motor mounts will line right up and your stock transmission will bolt right to the 3.4 V6. There are a lot of threads about dropping in the 3.4 on yotatech. If my runner originally had the 3.0 in it... I would have went with the 3.4 instead of rebuilding my 22re.
Good luck!