I have a MK2 GTI 8v and have the standard air box with the wings side drilled out for better flow. Its got a standard GSF panel filter in there and it seems pretty responsive and sounds alot better then my friend GTI with a K&N. Its time to change the filter now as its been in there for 6 months and it like it change the cheapy ones oftenish. I think i might go for the K&N performance panel filter as thats what was in the car when i bought it, but i got rid of that a few days into ownership as it was tatty and pretty useless. Its either a new one of them or a enclosed cone style, I'm swaying towards this as its got the heatsheild built around it and i can relocate the intake down at the bottom of the bumper so.. I'd rather keep the panel filter then just run a open cone style though, as the intake heat when you idling and driving is still alot higher then what it would be with a enclosed type, and my car has a rallye front end with a GTD rad so there isn't the usual open space between the rad and lights, so even less air flows through when I'm moving.