Yes that is legitimate. And it's recommended that you start your own thread instead of posting on a thread from 2008 next time. You should be able to tell how close the filter is to needing to be replaced however by looking at the filter gauge in your engine bay.So I have a 2006 ZX3 that apparently has a lifetime filter on it. I'm being told that I can only get a replacement through the dealership and that it's going to be $300. Is that legit? I am really not keen on spending that much on an air filter.