I am one who is not opposed to just freshening these engines.
I generally find the cylinders in fine shape and cranks measure perfect. I rering the pistons and reshell the bearings and the engines go a long time again.
I choose rings that want a smooth bore, this excludes Hastings and chrome rings.
Save your money on machine work and spend it on factory seals and gaskets.
Do not surface the head unless it really needs it. By surfacing a head it may flatten the mating surface but now the cam bores are no longer straight.
I have also had problems with aftermarket oil pumps. I have experienced sticking oil pressure relief valves not allowing pressure at startup. If you are on a budget inspect your pump and reuse it if it is good. if you have not had a bearing go bad the pump is generally fine.

Now if your budget allows, do a full and proper rebuild. But use as many factory parts as you can. For Mitsu engines they are generally better than the aftermarket stuff. Heads for the 2.6 excluded.