I thought that somewhere I read that the Audi RS4 engine (4.2L naturally aspirated V8) was helped in development by one of the guys that created the high revving S54 engine (3.2L naturally aspirated I6) from the BMW M3? Does anybody know if this is true? If so I find that very interesting that lines can be crossed like that between competitors. Either way they are both great engines, producing a lot of power for not having forced induction.