Hi. I'm new to these forums but i can see you guys know your stuff so figured asking people here would be worthwhile.

I drive a 1995 model 3 door Toyota Prado. She's running on her factory 1KZ-TE 3.0 turbo diesel engine and original 5-speed manual transmission.
However, the engine now has quite a few years on it. It has started drinking oil and giving more than usual black exhaust smoke. The engine has lost some power since i got her.
Now I am faced with 2 options, overhaul the engine, or a complete engine swap.
Personally i would prefer an engine swap because i want more power from her. The vehicle is mainly for road use, although I do enjoy taking her off-roading every once in a while.

From what I know, the model was offered with an optional 5VZ-FE, so that engine fits perfectly in the engine bay with minor engine mount alterations if i am not mistaken. However, I have driven a friends FJ40 with the V6 and auto transmission, and personally, I don't think it is going to be such a huge boost in power. Then again, the LJ72 weighs much less than the FJ40 so i am not really sure what kind of power am i looking at with that engine.

The other swap I can make is the 1JZ-GTE. From what I have heard engine is not such a good offroad option. However, i am still keeping the JZ option open if there are other suspension mods that give a better road balance. The engine is very powerful so safety is also a concern.

The third option and the one that i really want is the 1UZ-FE 4.0L v8. The engine is not that expensive and very reliable. However, i am not sure if it can fit very easily in the LJ considering it is a considerably large engine. I have read about some successful swaps that have been made but there isn't much information available for this particular swap, hence this post.

Lastly, I am open to any option and suggestions as long as it fits my needs of a balance between road and offroad performance. If there are any mods that can be made to any of the above mentioned engines for a better fuel consumption, please do mention.

My main priority here is power. I am looking to keep the manual transmission as I don't find driving an auto very enjoyable, and a practical fuel consumption.

Any help regarding this would be greatly appreciated.
Thanks