I think you need to decide what you want, not us. Both are nice, BTW good job man
Here is the deal for those cars on the street.
Which car you get kinda puts you in a social group.
Those cars are at the opposite ends of the spectrum.
The Cobra has more prestige. However, the stereotype of the people who drive them is bad. Either girls or rednecks.
The subaru will always be with whatever you do to it just an asian car. People who drive them are usually into racing and driving like a moron. "Ricers" Maybe you can help reverse the stereotype

While both cars have those negative aspects. That really shouldn't affect your decision. Just something to think about with whichever you choose when you are out
From personal experience...
I would go with the mustang for a car that is more fun to drive. While everyone preaches the reliability of the asian car. Personally I wanna have some fun, and the impreza can't deliver in the torque department like the mustang. There is something to be said for raw power of the mustang( putting you in your seat, you could argue the same for the feeling of the turbo doing the same, but its not the same. The power just slaps you and says I'm here, that does not happen in the impreza
While the subaru has the "reliability" and the AWD. I would still go with the mustang. Also has some heritage on the impreza, at least amongst americans ( I sense some punching back comments coming after that remark)
P.S. as we all have heard no replacement for displacement.