Yeah they know their stuff, they deal with all kinds of subaru issues. Hell its the only true subaru dealer/repair shop in the area that I know of, we got lots of Opel or other dealers that claim they work on subarus, but really only got a banner in the parking lot that says subaru.
There was another american with a simular motor issue and they tore into it and ended being a bent valve of some sort. They have done work for me and several other subarus here in graf and vilseck, its only a 40 min drive for me and def worth it.