I don't know about the air filter, but my guess is that you are quite right. And as for the armrest extension, you are definitely correct. Buy the part, install yourself, is a piece of cake. Also, for what it's worth, my dealer was telling me you could find the armrest extension on ebay for less than the dealer was selling it. I didn't have the patience for ebay, so i bought it from the dealer (and had them install), but just FYI I guess they're on ebay for $10 less or so.