Hi, just got a great little copen for my wife, its the big 40. Its sat in the garage waiting for the big day, ive sorted the paint work, got afew nice leather bits with red trim from ebay, red floor mats and a nice chrome and wood boot rack. But id like to improve the performance alittle, or at least make it sound quicker. Ive seen lots of info on here regarding different air filters, the best looking like the hks mushroom, ive been on ebay, but there are many different sizes and i could find a kit. Does anyono know the size hks filter i need along with any other parts?