ORIGINAL: TheX

Hey, it must be possible, look at all them cars with dual fart cans and they're super hotrods with no other work done.

ORIGINAL: custumize_RR

Increased HP happenes when you allow an engine to breath better. i.e. K&N air filter, and Performance exhaust system. What happenes is that when you increase airflow threw the engine.The E.F.I system wants to keep the stock fule to air ratio determined by the computer. Once more airflow is introduced the injectors will deliver more fule into the mix to fix the ratio and in which case, increasing HP. It's not magic... It's mechanics. : )

Also when pistons moves, it sucks air obviously,stock air filtershave lots of resistance, adding a K&N would lower the resistance.if there is less air resistance from your airfilter, results?? you Guessed it. Same thing happenes when you change your stock velocity stacks.

The same concept also applies to the exhaust. Larger, smoother, aftermarket exhausts have smoother bends and larger bore tubing creating lamnar air flow as opposed to stock which is more turbulent. This terbulance adds backpressure adding to the risistnace of the piston coming down robbing the engine of performance.

So as you can see... It's not magic... It's mechanics. : )