If the filter was crushed this means it cannot take the oil flow required by the engine and there is a pressure drop starting at the oil filter. In a band new engine that probably wont make much of a difference, but with the small wear here and there leading to a minuscule pressure drop each the critical limit is reached. As we can imagine wearing of the cam ledge will result in a slight drop in the oil pressure in the head and not a significant one. The vanos problem occurs from time to time and not every time the engine gets hot. This makes me think that higher grade (high quality) oil may help too.