<div class='quotetop'>QUOTE(RedHeartbeat &#064; Feb 4 2006, 10&#58;31 PM) [snapback]43611[/snapback]</div>
Imagine, a naturally aspirated engine where the spent gases were not only pushed out of the head but drawn out also.
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That is exactly what an x pipe does, now it should also be matched to the right size pipe diameter also. You use different sized exhaust to speed up and slow down exhaust gases. If you want torque you use a totally diff setup than if you want horsepower. To get the most out of your exhaust sytem takes a lot more than just a standard sized pipe. Yes an after market most of the time will give you better hp numbers but not what a truly tuned exhaust would for just your application. The manufactures could not make the money they do by doing one off for everyone. Not everyone wants the same thing from there truck or car. Similar yes but not the same thing.