I have an 07 boulevard 1400 (carb) and i wanted to change the slip-ons to a set of cobra´s, to wake it up a bit, not from the main headers, but just the slip-ons or mufflers. do anybody know if i would have to jet the card or leave it alone. i´m after getting mixed reactions, some people say don´t and others so yes you have to jet. do any body have any advise or first hand experience