I have noticed a bit of an increase in performance aswell, It feels more responsive now. in All Gears.
Panel Filter (piper cross) drilled box, cold air feed direct into box.
Go 4 the Panel filter. Least then u can drill the box and if u dont want toooooooooo much noise then dont drill loads of holes, all depends on how u want it sounding. only drill the bottom of the air box on the drivers side. (i did)
L8r