If you look on the IS200 forum, theres a topic from Sprinter, he made his own system with a Apexi filter. He makes and sells them, but hes also got all the parts listed down u need, roughly around £150 i think all in all. Pretty easy to do if youve got a weekend free. And it looks the dogs nadgers! B) if you need any ifno ask him..im sure hel help, but its a really handy post.