[Backtobasics]

Most of the S10 had a "cold air" intake base, where the air cleaner is ducted to the core suppor by the radiator. It could be adjusted to draw air from behind the radiator for a warm air intake. Drop in K&N filter?
I agree, full tune up, carb adjustment, etc would be in order.
Exhaust already has a "tubular" type exhaust manifold (mine did anyways) that is better then a log cast iron version. With 140K, I would consider a converter replacement (original may be the dreaded "pellet" style, incredibly restrictive and failure prone [expecially behind a carb]), and a lower restriction high flow muffler.
The existing lowering should help aero. A cheaper tonneau cover (soft vinyl) would be in the 225 range, if you wanted to go that way.
Roll pans are generally pretty cheap, if you wanted to ditch the weight of the rear bumper, and could be modded for aero, if you wanted it to not act like a parachute.

In general, the columns are "theft encouraged" GM so a collar might be wise.
Door hinges wear, particularly on driver's side.
Radio is INCREDIBLY easy to steal, so hide, relocate, or glovebox if you want fancy tunes.
Mine liked thicker oil, bearing tolerances got loose, and a new oil pump helped, but ultimately needed a crank kit and bearings to remain alive.