UPDATE: well never buy did buy another engine, PXed the car against another outback, a 2.5 and a few years newer, lost a fair few quid but got a decent deal on the 2.5 Outback, drove it home, over 220 miles, runs like a dream, guess I'll just put the H6 down to experience, the dealer wasn't bothered about the noise, I'm guessing he made his money when he took the car in, he says he'll just punt the H6 through the auction, I got £450 for it against the new car (well a 2004 model), all in all I'm pleased with the way things have worked out even if I have lost a few quid.