I'm surprised liberty told you they won't insure it I've had all my subarus apart from my current forester with them and they were all turbos and all jap. I started the policy with a sti type ra which I had for a couple of years then had a b4 legacy then a classic sti then couple normal cars then a classic wrx. I only left them last year after losing my no claims for a fire I'm with first Ireland now and they were very well priced on a t sport corolla and now the foz but give them a bell I wouldn't be surprised if they'd quote you on a turbo.