I agree with Mr. Shiftright. Avoid the RS because it only comes with the slightly quicker 2.5. Instead, consider the Impreza L up to year 2001, as it comes with the bullet-proof 2.2 engine. Not only is that engine not prone to head gasket failure, it is an excellent engine for you to learn to do your own routine maintenance. I can't think of a car with an easier to change oil filter, plugs, or fuel filter.
The insurance should also be cheaper on the L model than on the RS for a young driver.