Don't worry about the engine, they don't wear out. They blow up frequently but that's not km related. If they are maintained, not abused it's not uncommon for Suabru engines to still be strong after 400,000km.

A well looked after WRX will still be free of squeaks, rattles and visible wear after 200,000km, if you don't believe me I'll show you mine. On the other hand there are cars around that have 50,000km on the odo and the seats, carpet, door trims, steering wheel are worn through. Don't judge a cars condition by odometer alone, plenty have been tampered with.