More airflow = more power.  This is the most basic factor to consider when upgrading the performance of your Diamond Star.  The best place to start is elimination of the restrictive stock air filter.  HRC offers these K&N air filter upgrades.  They simply represent the best HP increase per dollar while also carrying a MILLION MILE Warranty!  Washable and reusable, this will be the last air filter you ever need to buy.  The Recharger kit shown includes cleaning fluid, filter oil and complete instructions for servicing your new K&N.