At one time Japanese regulations prohibited engines in that country producing more than 274hp, and oddly enough a wide array of different engines were all rated at that same level. Given the actual performance of the cars, it was clear that many manufacturers were sandbagging. Audi appears set to do the same with its uber-powerful RS6. The twin-turbo V10 is expected to carry an official rating of 571 hp, but the actual output could be as high as 610hp. Does anyone actually need this much power in a sedan or wagon? Of course not, but sign us up anyway.

[Source: Motor Authority]