what kind of Performance parts can install on a stock 96 subaru motor to give it a little horse power boost?

If it really is just a little more you are after, a full cat back and an open ended intake will give you close to 10hp. Add headers and a high flow cat and maybe another 10 to 15hp. The older models will respond to these basic mods pretty well but I will say that for about $700, 10hp may or may not be noticeable. The next 10hp will cost you about another $1000 and while you will probably feel a 20hp increase, you will probably just get used to it and wonder why you spent so much. I think the money could be better spent on a good suspension set up. That is something you will feel and appreciate for the life of the car. Plus, around a track, a good suspension set up will likely turn in better times than just adding 20 more horsepower. Just something to think about.

Get Ebay Equal Length Headers + full exhaust. And get a cone filter on there. May not help much with power but it's cheap to do and adds a nice sound at WOT (Wide Open Throttle) on the 96's.

It's a waste of time unless you have a factory turbo.