Cold-air intakes promise more horsepower and a louder engine sound, but how much performance do they really add?

The purpose of a cold-air intake is to find cold air in an otherwise hot under-hood environment. It can do this by drawing air from above the hood, under the front bumper or a spot inside the engine ...

One of the first modifications many enthusiasts make to their ride is adding a cold-air intake. This replaces the stock intake, a complex, convoluted contraption of pipes and baffles that keep the ...