Though I own a 180sx and love it, i'd have to say the WRX is a better performer and a more practical car.
Also, you can have some fun with it more "year around", and the 4wd is a hell of a lot "safer".'
that said, RWD can be a lot of fun. More economical for cruising in (less drivetrain loss).
I can also fit two people in the 180sx (fold down rear seats, fold forward fronts, practically a double bed, or a car full of camping/dj gear.
We can't really recommend one as "superior" as they are totally different vehicles, so it comes down to PERSONAL preference.
Also, though you thirst for power now there will come a time when you have a 180sx needing new bushes, tyres, brakes, and interior clips/screws because you keep taking out panels, that you f**king wished you just bought a "newer" car to start with. har har.