If you already decided to keep the bad boy running most of these questions aren't necesary to begin with.
Based on your questions you don't seem to be that sure about what step to take.
As you may already know this is isuzu 1rst 3.5L. Is a stroke version of the older 3.2L
Unfortunately isuzu engineers were not that accurate designing and testing this engine so most of us had to pay for that lack of accuracy.
If you gonna keep the bad boy one of my suggestions is to rebuilt the engine with good/quality parts,not neccesarily OEM,instead research companies that supplies rebuild kits that meets or exceeds OEM standard specs,especially if they produce a kit that gets rid of the oil issue.
You can also get a 2002-04 low mileage axiom's long block engine with at least 3 to 5 years/unlimited mileage warranty with the "X" as the eight digit on the VIN number.
If you have spare $$$$ i'll also do a transmmission overhaul so you will be driving a almost brand-new VX.
How much $$$ members had spent in the past to overhaul their VX's engines is relative as the cost to rebuild varies from state to state and from time to time.
How long it could take to get the job done also depends,if your mech gets into it with no delays you can probably have the engine put together in few days
What kind of parts other members used is also relative in my opinion,but one thing for sure the more new parts you get in there the better
Pros & cons ?
The pro is that you will be still driving a VX.
The con and probably the worst one is your engine go BOOM again
If you can't bear with the fact about another isuzu engine then read,research and put together all the facts about a non-isuzu engine,there are few members that did the miracle and are satisfied with the happy endind. (not that happy ending your twisted mind )
Dakar was just the begining.