K&N filters are good if you enjoy "messing" with your car a lot, i.e. hobby sort of. Your OEM filter is fine and does not require anything other than periodic changing, say every 30k or so.
The answer is based in - do you want to "play" with your car often for a hobby or not?

All I can say is that our 04, XC90 has never leaked and now is at 54k miles. Good Luck to all on getting their water problems fixed.