My original question was to find out if there was anything between the K&N and Pipercross which no one has really answered. I now have a Pipercross on loan and there is a some improvement in performance - seems more responsive on the throttle. Whether you'd notice any difference between the two makes I'd thought would be negligible.

Which ever is the cheapest! Simple equation, is it not?

Go for the one that gives a free sticker

you get two stickers with k&n