The triple layer foam design ensures an exceptional level of engine protection in any conditions. Benefits of a Pipercross panel filter 30-40% more air flow over your OEM paper filter.
This filter has made the engine freer revving and the car feels a little keener as a result.
When you open the box, there is a leaflet saying 'for motorsport only, clean every 1000 miles'. I think that Pipercross are being cautious with that, from experience and that annual cleaning would be fine, in normal (not very dusty) conditions.