I wouldn't buy without a test drive and it was hard enough to test a wrx! I had the same, sti or wrx dilemma and I thought of what my old Dad would say. "Get the sporty car, not the real sports car, 'cause you're gonna wrap the sports car around a tree! A sporty car is still sexier, faster and better handling than a regular car!"
However, the wrx is FAR more than sporty, and I can picture Dad saying, "It's real nice - now don't wrap it around a tree!" As believe me, one could easily wrap the wrx 'round a tree. 265 hp is plenty heady and tricksy enough, you'll have a lot of fun and it's a tad cheaper to insure, to service and fix and does't have the 'Hey copper, please gimme a ticket!" spoiler (although I confess, I love spoilers, I"m 50 going on 14).