[WolfpackS2k]

Regarding engine swaps, NO they are not illegal and I don't know why people keep saying they are. I can certainly see them being illegal in the People's Socialist Republic of California but that is a state issue. In most, if not all other, states they are perfectly legal and are allowed by the federal government. According to the Feds an engine swap can be done if 2 things are met:

1) The engine being swapped into the car has to be from the same model year or newer (i.e. swapping an LS1 [from a late 90s Camaro/Corvette] into an FD RX-7 [made in 92-94] is perfectly legal but swapping a late 90s LS1 into a 2005 S2000 is not).
2) The car must pass the emission requirements for that model year car. If it's OBD-II (1996+) then it must adhere to those requirements. If it's from before 1996 there's a good chance it doesn't even have to pass emissions at all, other than a visual check to confirm the existence of a catalytic converter.

Hell, there are a lot of states out there that never do emissions testing on vehicles..ever.

Originally Posted by Anaxilus

To a point. If you have a big fat M or AMG sedan and the brakes and tires are done after 3 laps, I'd say driver skill doesn't matter much.

Except give any M or AMG car track pads and the brakes won't fade. Tires might overheat from the heft of the car, but you can upgrade the tires as well to fix that.