Actually, the Virginia Beach facility has two primary product lines - polymer (plastic) components and guide bars. They do not make engines there - they assemble products from locally made components and engines imported from Germany. The carburetors used to be made in Germany as well but the last I had read (several years ago) was that Stihl was making all of their carburetors in Taiwan. Chain saw chain sold by Stihl in North America is made under license for them in Portland, Oregon by the Oregon Chain company - the world's premier maker of chain saw chains. At least as of 2004, that was true - my nephew is an engineer with Oregon Chain.
I toured the plant in Prum in 1981 as part of arranging a deal to provide chain saws to UN sponsored timber management practices training facilities in India. It was a quite amazing facility. They manufacture not only the magnesium alloy engines there, but many other magnesium alloy components used in various automobile makes, Airbus and Boeing aircraft, and Saab military aircraft built in Sweden.