bumping up your tire pressures just a little bit will do more for fuel economy than a CAI will, lol
example: if you normally run 35psi, bump it up to 40..
tires in general can have a pretty profound affect on fuel economy.. the formula used (hard/soft), tread design, type will impact fuel in one way or another.
driving style will also be a factor.. if you tend to be an aggressive driver.. jumping off the line at lights, not slowing before stop signs (ie waiting as long as possible to brake) will eat up a fair bit of fuel economy. average speed, too. if you are one to routinely run 10-15mph over the speed limit on the freeway.. try dropping down to only 5 over... the faster you go, the more fuel you are using.
basically, there are lots of little things you can do that dont cost anything at all to improve your fuel economy. on that car, i would expect around 27mpg overall.. you might get it up to 29 if you are lucky.. that was the best i had ever gotten out of my 90 Legacy wagon... same basic car with a few cosmetic changes.