I don't want to be all doom and gloom either but going by its MOT history I'd get it up on a lift and inspect the underneath to see how bad the corrosion is first, it's had advisory after advisory for yrs for corrosion and Subaru's are prone to rust, it might be nowt to worry about but you don't want to chucking loads of money at a car that might turn out to be a rot box, not trying to alarm you or nowt sorry.