peter replied:

Hi Nigel
The answer is DEFINITELY. Ive used them for years on motorcycles & cars. Ive not found anything as good or reliable. I use them on my NH Pajero and it has made a noticeable improvement over the standard filter. I also have dual fuel and a 2" sports system and the K&N improved over and above these as I fitted it last.
Regards

Paul replied:

Nigel, It depends what you want it for. K&N are a performance filter they work great in performance cars and motorcycles as they are a high flow filter. I have one in an FZ750 bike and the improvement is noticeable. For a 4WD you are better of going with a finer filter as they have finer filtration, they are also more easily serviceable in the outback. Due to being made up of 2 parts, an oiled pre cleaner and an oiled element. You usually only have to clean the pre cleaner.