New HMF Competition series full exhuast system

[Ou812cd1]

Hello all newbie here....
I just bought my son a HMF competition series full exhaust for his 2006 Honda 300EX along with the jet kit for Christmas. My question is the Basic Jet Kits Includes: Individual Keihin Hex Jet: 120, 125, 130 , which needle is going to give him the most power? Also he already has a K & N filter installed. As you all can probably tell this will be my first go around adding an exhaust system and a jet kit to an ATV. Thanks in advance for any help!!

[patches206]

The jets are easy, just follow the instructions.   It will give you the best jets for the elivation we are at which is basiclly sea level.  The HMF exhaust is easy to install and a great pipe.  Welcome to the site.