Also, the number of car manufacturers outnumber the number of car engine manufacturers - so if one company which actually makes engines (cough) optimizes their engines for testing, several car manufacturers may be caught with their trousers down. (Which, I am sure, will lead to all sorts of interesting lawsuits.)<p>For instance, the engine in cars as different as the Land Rover Defender (sadly, no longer among us) and the Volvo, say, S80 is basically the same Ford-engineered unit.