Most 2.5 Subaru's take a little over 4 quarts of oil with filter.
Add 4 quarts and start engine.
Shut off engine and check dip stick.
Make sure oil light goes out.
If you have a gauge it should read when you start it.
Should bolt right up. Take pictures of your current one and compare it to the new one. Model didn't change until 2003.
10 minutes or less
Take the distance traveled (X) and divide by the mpg (30)
1997 subaru impreza consume 5.8 litres of oil
4.2 quarts
It takes 6.9 qts of oil.
The best answer is that you should take it to a service station that will recycle your oil. Guess I need to ask if you have ever changed oil in a car and if you are seeing something different here that is a problem. --Ken
Usually take the car to the nearest Subaru dealer and have then fix it. They invented it, they should fix it.
It would depend on the model year and where you take it to trade it in on how much you would get for your trade in but yes my search says you can trade in your Subaru Impreza.
Try 87 Octane, if it does not "ping" excessively you should be OK
3.7 litres
5 qts.