We would need to continually write K&N to get them to produce products. Thats what we did for my old Maxima and we were able to get aftermarket support when originally we had none. Now they make Altezza's, turbos, indiglo gauges, and other parts that would not usually be associated with a Maxima. Its all in numbers. If K&N thinks that there are a lot of c230c owners out there they might make a filter or cone adapter.
Erik
Erik