I'm always in favor of retaining engineered components/systems. I was just checking to see if there was something I missed in regards to efficiency, or well documented failures, etc.

The balance shafts ARE a documented failure point, or at least the bearings are (probably because they're a PITA to replace and get skipped during a rebuild). Plan on installing new balance shaft bearings with your overhaul, as well as a new oil pump. You might also want to search for the thread on oil pump relief valve shimming as described by FastEddy - good knowledge there.

95 Montero SR 3.5
OME shocks & springs, cranked torsion bars, 2" body lift, 3" gas tank lift, 4.90 gears, Aussie front locker, factory rear locker, Aisin manual hubs, Roger Brown Rock Sliderz, 315/75r16 (35") tires, 2 1/4" exhaust with Magnaflow muffler