The 3.4 is supposed to be quite easy to swap in place and is a great motor. I would not go to the trouble to swap in a 22r unless it is just a cost saving measure. If you have the time and money the 5.3 would be the best option. It would probably beat the 3.4 in gas milage and would have a lot more power. I have my doubts about how long a Toyota case would live behind a modern v8. Your talking more than twice the power of a 22r.