Originally Posted by PoManzAWD
Front stabilizer bar end-link would be my guess, although I have not heard of them as being an issue on the 2010+ Legacys.
On many makes/models, it's not uncommon for those to go out early and at low miles. No harm aside from clunks over bumps. They're real easy to replace. I know I replaced them on several later model, low mileage vehicles.
Thanks Joel, I checked that and it seems tight ( what a stupid design that little thing is ) I made the noise happen repeatedly yesterday and it's loudest right under my legs driving . Sounds like a hollow clunking - like something is lose in that corner. No difference with ths window open