Staffi is right, an import Sti wagon would be better spec than a UK Turbo. But as he says, they come into this country set up for jap fuel(100+ RON), so if you buy a car which has been in this country for 4 years for e.g running around on UK fuel you're asking for trouble.
In that case you ideally want to buy a car which has been enthusiast owned and mapped as soon as it got the the UK, or buy a fresh import and map it straight away.
It's people that don't do the above that end up with knackered engines, and then complain that they are made of chocolate!