Porsche, as part of the VW Group, is not averse to sharing parts and platforms to reduce costs. The brand’s upcoming baby roadster, positioned as the new entry-level Porsche below the Boxster product line, will share underpinnings with VW’s Bluesport and a similarly configured car from Audi. It was widely accepted the three individually branded cars would share a single range of engines, too.At the Detroit auto show, however, Porsche’s research and development boss Wolfgang Durheimer confirmed that "we have a four-cylinder boxer engine under development".MAINSTAY MOTOR?This new forced-induction flat-four, thought to be of 2.5-litre capacity, will be a standalone Porsche engine for exclusive use in its version of the new VW Group roadster. Such an instance of Porsche engineering individualism goes against the grain of the VW Group’s much vaunted economies of scale when sharing components. The new flat-four engine should produce around 264kW in peak road-going trim - enough, possibly, to make it a mainstay for the 911 range in future. Durheimer says the flat four,"could be applied, if necessary, to the 911".