The 3rd generation civic you have is a great car, they have alot of room inside because of the solid rear axle, they are light weight, have a back seat, and fuel injection, I hear people average low 40's for mileage, my first car was an '84 civic dx hatch back, I averaged 42.2mpg over it's life with me, if I ever found a civic si like you have I would defently get it.
someone on redpepperracing.com was selling hand made carbon fiber front end parts at reasonable prices, not sure if they are still avalible or not, but if you have any damage it's something I would think about to save some weight, your car will also fit light weght wheels from other cars, like the honda insight, civic vx or hx, or even the light weight steel wheels from the crx hf altho they are not as pretty.
Years ago I picked up an '86 Civic (not the Si though, with the 1.3 I think?) for $265. I was startled by the mileage I was able to get from it without trying too hard - just kept my speed to around 55 mph on the highway.
I was shocked to see 50 mpg (US).
Welcome to the site.
(Hey Hockey4mnhs - I know an Ashley who's a guy. Can't assume anything out here.... )