Your 97 is a Gen2, not a Gen2.5, so the most similar year to your vehicle will be a 96. However, you have the 6G74 3.5 SOHC engine, where the 94-96 SR has the DOHC version of that engine, so you'll need the engine info from a 97-2000 model.

As noted above, the FSM is by far the best source of repair info for your vehicle - Haynes and Chilton's manuals make great firestarters.

As noted above, the valve stem seals are a common issue on Mitsu engines, and can be replaced without removing the cylinder heads. If you're having a shop do the timing belt and associated parts, make sure to check that your engine has the updated crankshaft bolt and washer installed - if not, it needs to be done with the timing belt and torqued to the updated torque spec. Replace the timing belt tensioner when doing the timing belt - use an OEM Mitsubishi part only, the aftermarket parts seem to have a high failure rate.

A timing belt service is a great time to have the radiator rodded out by a radiator shop - reinstall it with a new OEM radiator cap and thermostat, and replace any cooling system hoses that aren't in great shape, and your cooling system will be good to go for another 60k miles. Checking the fan clutch for proper operation is a good idea as well - it should spin freely when cold but be almost locked to the engine when hot.

The "handle and spring" is actually a hook to hang the spare tire on while you install the lug bolts. I ended up buying some extra lug nuts and wheel studs, cut off the threaded portion of the studs and epoxied them into the lug nuts to create lug bolts to hold my spare on. Alternatively, you could use the same process to epoxy the studs on the tire carrier.

Your factory suspension is far more capable and comfortable than most any other 4x4, and really needs no modifications to be seriously competent off-road. Larger tires will give you a bit more ground clearance but you'll feel the difference in the amount of power it takes to turn them.

This forum has a huge amount of information within it's posts - some searching will give you much more information on everything mentioned above.