I also read that insurers insist on a Thatcham Cat1 alarm, or equivalent. As Japan is a civilized country, they don't need alarms as standard so any grey import would have this retro fitted.
There's an importer outfit in Kent (Edenbridge) that might be worth a visit.
My 2006 Outback needs replacing after 15 years of ownership so a 2.0 Levorg seems a logical choice
I'm in the UK so the only STIs here are grey imports, but I've heard insurance can be expensive and difficult for these. Also, I'm concerned that 296HP too much even for the for the stronger CVT...