Have fitted my foam air filte from pipercross, from advice, a foam filter in the standard airbox gives better output figures that a bolt on after market replacement hose & cone filter. Well if you remove the clips & clamps as stated by another member previously, the airbox is then mounted on 4 rubber mounts, you need to tug the box / cover pretty hard to snap it off, just check the 4 rubber boots are still on the underside of the box when you pull it off. If not find them quick, usually the front 2 come off, found just infront of the block in amongst some wires. Best bet to remove the box completely from thecar turn it over to remove the 12 or so philips scews to get the airbox open. If youve done it once, 10 minutes to change a filter. One pointer, when plugging the air hose back into the MAFF on the side of the airbox, grease the fat rubber seal with some washing up liquid or similar, coz its a bxxtard to get back in otherwise.