I'm always going to have to suggest an STi. :tup:
A WRX is for someone who doesn't care much for performance or isn't going to use the car more than just a daily driver. However, the exception comes in with a 15+ WRX now as they are finally refined and are more than enough, especially for beginner drivers. :tup:
An STi is going to have the perks that matter since it's the higher tier. Improvements include: suspension, brakes, engine, power, handling, aerodynamics, and overall performance.
You should either get a ride in both cars or drive them yourself to get a feel of what these cars are all about. The GR hatches 08-14 are great cars and have had great reception with their cargo room. :tup: