anypne planning on running a K&N filter read this first
it doesn't really matter that it is on a deisel, due to the volume of air they shift the filter is more important than a standard petrol.
but given most of the cars on here are turbos and chipped/tuned/fettled and massaged the filter is more important on our cars.
check out how badly the K&N does in all tests apart from restriction.
The only reason I can see that K&N claims increased horsepower is by having the least possible restrictive media that lets anything apart from gravel through.
what makes it even scarier is that it seems to clog up very quickly as well.