IMHO, you should also consider airbox removal vs. airbox modifications. You won't miss it, not even a little bit.

2004 TA/19'slash cuts/150/45/N3RF TBS needles,no shims/2 1/2 turns out/FZ1 springs/clean balanced carbs/pods/18/44/EK chain/TBS cush drive/Commander IIs/Armstrong GG pads/TTP firestarter/TTP safe start/green springs/Pretech 6 pot/Ricors