The first step to increasing the performance of any vehicle is the use of a low restriction intake system (not the manifold, yet). The most gains for a bolt on, in general, will be found with this one modification.

In choosing an intake, the best will pull air in as far away from the motor as possible. These are cold/cool air intakes. The cooler the air, the higher the oxygen content, the greater the bang.

The difference between cold air intakes and short ram intakes is minimal, but there is a difference. Generally, a short ram intake will give you low end (off the line) horse power/torque, where a cold air intake will give you power in the upper part of the horse power/torque curve. It depends on where you want the power.

The inherent fault with a short ram: It pulls in warm engine air. The inherent fault with a cold air: It can pull in water via a puddle. And that can destroy your engine, creating a hydro lock and cause severe internal damage. Water bypass valves to counter act this are available but they are not 100 percent effective.

On the positive side, short rams will launch you off the line, and cold airs will give you another 1-3 horsepower overall.

One alternative is the K&N drop-in filter. It increases CFM's into your motor, adding power, but it’s
routed through a restrictive system. Still, it’s another highly recommended modification. The larger the engine, the greater the increase. But all modification will increase in power with the intake modifications mentioned above.

Intake manifolds are tricky to determine when and where to modify. The science behind it differs from large cubic inch American muscle and smaller import tuners. Here are two good examples, both with stock motors:

1.) A 1975 Corvette Stingray. We built it up a little, adding a larger high rise intake manifold. This Corvette woke up and became a “beast” throughout the entire power curve.

2.) A 1996 Civic EX. It was given a larger intake manifold and “fell on its face” until about 70 mph or higher.

The reaon: A larger cubic inch motor can use the extra air, a smaller motor must have a balanced and "tuned" system for its setup. Honda has mastered making power-swapping Honda OEM parts. They may use a Honda Type R intake, which is slightly bigger. But it gives more power due to its balance in size in relation to the size of the motor.

All after market intake manifolds for imports are generally much larger. If your motor does not have the modifications to support this, you will actually lose power bolting these on. The modifications that support such an upgrade on an import are usually boost pressure (turbo or supercharger) or a high compression built up motor. These setups benefit greatly from a larger supply of air.