Lots of great info. Thanks. Would there be a way to determine ahead of bumper/winch install if I would need to upgrade torsion bars vs adjust or reindex?For our 100 series the front is actually supported by the torsion bars and not by the shocks. The OEM (none AHC) torsion bars can be adjusted to support a good amount of weight. Note that vehicles with AHC have a lighter weight torsion bar that can not support the full weight of the vehicle. People typically switch to thicker torsion bars (which means a higher spring rate) when they add a bumper and a winch.
On the rear, the springs support the weight so again not the shocks.
In both cases, the OEM shocks can work, but people typically switch to Ironman Foam Cell Pros, Tough Dog Foam Cells, or many of the other shock brands (Dobinsons, Icon, and Radflo to name a few of the higher end ones) to get the firmer feel from a shock that has different internal valving from stock.
At the age and mileage of our vehicles the original suspensions are typically worn. If you are still on the original springs it is likely that they have sagged a few inches. For springs, new OEMs are typically double the price of new aftermarket so people usually go that route since it also means they can handle more load. For shocks, new OEMs are super cheap so it is typically recommended to give new OEMs a try to see how you like them before diving into the aftermarket.