K&N Race Spec Air Filter
Aside from eating a can of beans, the best way to get a significant boost in airflow is with an aftermarket air filter. K&N's Race Spec filter is built with two layers of a specially pleated material that's designed to provide minimal air restriction (resulting in increased horsepower and torque).
The filter fits directly into your stock airbox and comes pre-oiled for immediate use. For best results a fuel management system is highly recommended.
$79
www.knfilters.com