NJFZ1
Moderator
no.. it's rather important.
It's about maintaining proper back pressure at low / mid RPM for optimal power delivery.
You buy a header... you give up low-end power... but have slight gains in top end.
Yea, you're right about that! And if you do most of your riding on the street then you will probably regret getting rid of the EXUP because you'll miss that low and mid-range torque.