If you're in Japan and intending to personal import one back, it'd be worth looking into something that we don't get here. S201-S204, Spec-C RA-R, STI Forester, Version 5/6 STI Wagon etc.

Couple of tips I have:

Check for rust underneath. Not a problem in Aus but salt is an issue in parts of Japan.
Rear struts are known to knock in 01-04? STI's, can be fixed with having grease nipples fitted
Be wary of cars with stacks of gauges and electronic gadgets unless work can be proven to be of professional quality. Butchered wiring harnesses suck.
Check spare wheel well, radiator support, beneath bumpers etc. for damage/rust