Well thats clearly not designed for a Focus RS is it. At least the K&N Gen II and GGR housing were developed on the car they were designed for, compared to these stupid "universal" kits that appear on ebay.

As per the ad listing it's just a generic (and exceptionally cheap - for that read bad) universal item the seller claims "fits 99% of cars" - read that as can be bodged to fit 99% of cars but the small print most likely states no refunds if it doesnt fit the car.

If you want induction noise buy a Gen II - if you don't then just keep the standard airbox and fit an uprated panel filter