Do you have an upgraded exhaust?And also plugging up the muffler a little bit gives you more bottom and a smother hit to get to the top end. I my self love bottom end more than anything and with plugging it up you get more bottom and a smother transaction to mid all the way up to top. You lose horse power but not enough to feel.
Upgraded exhaust ?, meaning an aft market one, or stock ?
How have you "plugged up" your muffler ?