German luxury sports car manufacturer Porsche has unexpectedly had to lower its forecasts due to flood damage at an aluminium supplier. The Stuttgart-based company now expects revenue between €39 billion and €40 billion ($42.4 billion-$43.5 billion), it said on Tuesday. Previously, Porsche’s management, led by chief executive Oliver Blume, had planned for revenue between €40 billion and €42 billion for the current year. According to reports, the flooding of a production facility of a major European aluminium supplier is currently causing significant supply bottlenecks. “Body parts made from al…