Well I am very happy at this very moment. I have a 1997 Impreza L 2.2 liter and I was getting about 18-21 mpg... and I was f'en pissed off having to fill up every 4 days!!! Well, 2 weeks ago I bought a K&N Cone Filter (RU-3580) and a www.Kartboy.com
MAF Filter Mount. (total cost $75)
Well I can feel a definite increase in power and guess what!??!?! I got 28 mpg!!!
28 MPG, this is amazing considering I have floored my car whenever possible, and taken it up to about 100 - 110 mpg just to see how much performance it added.
For all 93-99 Imprezas, do this ASAP and you'll thank me!