Oil Capacity is 4.5 Quarts (4.3 liters) for the following models: 2002-2006 R50/53 MINI Cooper and Cooper S Hardtop 2005-2008 R52 MINI Cooper and Cooper S Connvertible
JdmMuGeNk20 Having worked on this car, I woukd say they went for the SOHC to save space, reduce cost, weight and complexity of the engine. Also in this engine family the other engines (1.4 and 1.6 NA) were not performance orientated, so the supercharged option was just a development of that platform. Thanks