if I am not mistaken the 320 and th 240 have the same air filter location.<br> <br> I have a c240 and checked c320 engine pictures and the <look< the same.<br> <br> you need to remove the air intakes (duct like plastic tubes getting the air above the rad). once these are removed, the entire black-grey cover (written mercedes on it) can be remove just by puliing upward. when you turn this part over, you will find torx screws on each side. filters are under these plastic cover..<br> <br> I just installed K&N 33-2181. they fit snuggly. not too sure about the performance gain though...<br> andre