They do make a filter that goes into your stock air cleaner box. Motorsport and other performance Z shops will sell you a cone filter with a nice, shiny mandrel bent intake tube for some big bucks. But if you're just so darn cheap (read - ME) you can't justify parting with your hard earned cash that way you can build your own.
I have a little how-to website you can take a look at. Other guys have some as well. I would post their urls too, I just can't remember them off the top of my head. ;^)
> Does anyone know if K&N makes a filter/kit
> for 280Z? I'm basically interested in any
> intake upgrade for the 280Z.