Welcome to the subaru world.
Some quirks with newer WRX's:
A lot of them develop a squeaky bearing around the clutch area, forget which bearing exactly, but its a re-occurring thing that happens at random milage no matter how many times you lube the bearing. The sedans have a few interior rattles that come from the rear shelf, and various other places. The engines are also pretty noisy, ticking from the valvetrain/injectors and turbo noises sometimes worry new owners but are normal. That's about all I can really think of, but I am sure there are more.
Oh, and changing spark plugs in a subaru is a trickier job than in most other cars.
Not sure if it counts as a quirk but these cars are sensitive to mods that change the airflow around the turbo, so intakes and downpipes need to be tuned for or your car is going to lean out and fall on its face.
The tranny's on these cars are robust but not bullet proof, and they are as dependable as the person driving them: do the right maintenance at the right time and it should last you quite awhile.