In case it is G11 - stay away from swapping any engine other than its stock petrol or diesel.
In case of G100, 1nzfe, Toyota 4afe, 4efe, 5afe are popular swaps. They are easy to maintain with wider availability of parts. BUT ......
first do a lot of research online, about what are essentials of swapping, read posts of other people who swapped the engine, what components are needed (our mechanics only buy you an engine and gear box, there are a lot of other components that need to be compatible with power house else it will be constant pain in .....
if you do not have much interest about bits and bobs of cars, engines, mechanical, electrical wiring stay away from swap for good. You will save your time, money and headache.
Auto gear requires checks 2 stone in addition to manual swap. You actually double the things that can go wrong with swapping a scrapyard auto gear.
If all of blah blah check list is ok for you then getting a halfcut with complete engine, wiring, AC, condenser, evaporator, fuse box, relay box, gear lever, cluster, mounts, bigger brake rotors, all sensors, fuel pump and filter etc etc is best bet.
If you go with purchasing engine only, you will be paying extra for all of the above side things.