When modifying a vehicle it goes a lot more easily if you get a good handle on what is the same and what is different from similar years. Catalogues do not always have very good year fitment information.
Look into what the differences for 85 were and it should help your search for 84 parts.
Things like a cold air intake a little ingenuity can usually build something that performs as well as kits at a fraction the cost. I know I have put PVC and plumbing rubber connectors under the hoods of every car I have owned in the last 9 years, and taken a hole saw to the airfilter box obviously on the dirty side of the filter. $15 gets me just as much power as a couple hundred dollar K&N kit.