Sounds like an idiot salesman. The 3 is built on the Ford global C1 platform which underpins the Volvo S40 and the European-spec 2005 Focus (the US-spec is going to stay on its current platform through at least 2006 with an update for 2005). The hard parts like floorpans, suspensions and such are shared but each company uses its own body panels, interiors, motors, etc.