I did exactly that. Took out the charcoal filter and dropped in k&n. No difference in performance or milage. I wouldn't do it again. It did come with some sweet stickers. If that's what you after you can have mine
You could probably do it in that time by yourself. You just have to take your wheels off and bolt the spacers on and then put your wheel back on. And I used loctite on the bolts on the spacers