An aftermarket exhaust, depending on make, may add 5-8-hp.
The best value out there, IMO, is the Flowmaster cat back for late C4s.
As for aftermarket air filter assemblies, there are only a few really work well because the stock air filter assembly was designed to support the LT5 which had 100 more horsepower than your LT1. What I'd do is replace the stock filter with a Green Filter and add one of the open-element tops. That's all I ever did on my '95.
That you have a 96 with an LT1 tells me the car is an automatic.
First, find out what axle ratio is in the car. If you DO NOT see G92, the car has the base 2.59 axle.
If it's the 2.59, your biggest bang-for-the buck performance mod on a car which is stock is to replace the 2.59 axle with the performance axle for automatics, the 3.07.