Works for me. I have a second air filter cover with holes. Duct tape covers the holes at low altitude.At 10000 feet, a little leaner than stock would be better, but at the bottom of the mountain you'd be running so lean that you'd be risking your engine. One solution is to have some holes in your airbox that you uncover at the top, and cover back up at the bottom.
Right on, how many and how big are the holes that you make?