The opposed six cylinder engine (boxer engine) is commonly stated to have balance as good as inline six cylinder engines. Yet, some sources attribute greater smoothness to inline engines. My own recent drive of a new six cylinder Subaru showed the engine to be less smooth than the inline six in my present car. Could the reason be due to the very thin crankshaft webs on the opposed six cylinder engine crankshaft? The six cylinder opposed Honda GoldWing engine wins praise for its smoothness, despite solid mounting to the frame. Is this because of having only a four-main bearing crankshaft, with thicker webs?