heres an intake mod i did recently to my 07 YFZ. it noticably incresed airflow, and is fairly easy to do. it took about an hour and all you need is:
-10ml socket and socket wrench
-Screw driver (+ for removing clamps)
-Dremel with a disk cutter
-Glue gun
-paper towel
-Sharpie or other permanent marker.
-common sence and a set of basic knowedge to get the job done right (LOL)
1. start by removing the seat and the four 10ml bolts holding the air box on. loosten the engine breather from the airbox. loosten the clamp on the intake hose to the airbox. now compleatly remove the airbox.
2. remove the stock air box lid and place it to the side. remove the airfilter and place it in a **clean** low traffic area