92 Mustang LX 2.3

[92LXcoupeNoob]

I have a 4 speed automatic LX and I want to do an upgrade to it because I find that I could really use a little bit more of everything. Before you start talking in a foreign language, I must note that I am a first timer (This is my first car, im 19 yrs old, uneducated on mechanics). My car is completely stock under the hood, despite that I have done a regular tune up recently and have a brand new starter. What can i do to add more horsepower, torque, and/or mpg? Ive gone to Autozone and they suggested an aftermarket Air Intake but how and which do i use? Also I thought about performance modules/chips to give it a boost. What can I do to make my 2.3 lighter, faster, and economic?