According to your signature, your 1FZ is getting up there in miles. Many need a full $$$$ rebuild about 350K miles.
I think the question is, when your 1FZ needs a rebuild, what do you do? Spend $$$$ to rebuild it or do you swap in a more modern motor? I personally think the 1FZ-FE is a s*** motor...there I said it.
I know what my answer was when I had to make the choice: L96/6L90e. IMHO, the best engine/trans combo one could swap into a 80 series. IMHO, the 80 series is begging for a V8.
I don't disagree with what many have posted about the LM2: Timing Chain, Oil Pump Belt, Limited Production Run and the questions of overall longevity and reliability.
To be fair, are we putting another 200K miles on these vehicles? Probably not...My LX450 is not my daily...