I got a 33-2116 K&N panel filter today for the stock air box and when I opened it the rubber seal had two rectangular tabs on one side. It didn't fit right because of these. I haven't heard anyone else mention this. The Holden cars must have a slightly different air box. I had to cut off the two tabs (rubber) in order to get a good seal. I hated butchering a brand new lifetime filter but I wasn't going to modify the air box. I just thought I'd mention this in case anyone else is planning on using a 33-2116.