I just bought this as my first car on Thursday. I would really appreciate some opinions on it as well as some help that I am needing. The INFL REST light is on. Is there something wrong with my airbags or does the fuse just need changed? I don't want to be driving down the road or honk the horn and the airbag go off break my neck. lol Also there is occasionally a loud rattling noise underneath the car. Is that just my heat shield or what? It makes it sound like a piece of crap! :/ Also any other cheap tricks or mods that would make my car faster or look nicer would be greatly appreciated!!! Thank you!

Here is a picture:

 

Oh my heck! I couldn't be more jealous if I tried! Total score!
Okay. First, the Infl Rest light is airbag related. But in the nearly 3 years that I had my '91 Camaro RS 5.0L, my airbag never went off, even when I rear-ended a Mustang at 5 MPH, but my airbag light was on anytime the car was running, the entire time I owned that car. I never investigated, I just didn't care.
The rattling, I have no clue.
Your first mods depend on how you're gonna use the car. If it's mostly sitting in city traffic, then start with a rear axle swap. This is to get better gearing. This is a fairly easy mod, you just go find the complete rear axle assembly from any '90-'92 V6/automatic Camaro/Firebird, and exchange that for yours.
This really won't hurt your average MPG. My '91 averaged 23 mpg both before and after, and I did recalibrate the speedo before getting the "after" number.
You just change the speedo gears to a red 17 tooth drive gear, and a light blue 45 tooth driven gear.
If this car is only for long road trips, with virtually no city use, then leave the rear axle alone, and start with the exhaust system instead.
The exhaust system is the second mod for city traffic.
That'll get you off to a fun start. ALL the info you need is already here on TGO, just do the searching and reading.