Tomorrow i am installing a Vance Hines muffler and dyno jet kit. My 2007 has no mods at all right now. Should I do an airbox mod prior to these upgrades? The airbox on my sons KLR looks like swiss cheese it has so many holes in it and it runs much better than mine. Should I do an L mod or just cut holes? How do you do and L mod. I know you cut an L shape in the box but I don't know how big or where exactly.