hi guys, here are some silly mod questions... 1. will a rear brake pump from newer 04' yz fit the old wr400f mounts? 2. will a 40mm crf carb bring on any benefits to a wr400 with hotcams and bigbore kit (440cc) or should i just stick on to the 39mm ones...? 3. and should i cut holes on the air box to make it breathe better? thanks for helping me solve all this mystery !!