My latest addition is this rather rare USDM carpeted trunk lid liner. This was only available for the American market, so being the huge fan of factory options/accessories that I am I just had to have it, even if it wasn't an original JDM item. A good friend in the US kindly sent it over to me and I installed it a few minutes ago.
The bare skin of the trunk lid is no longer visible, creating a more elegant and luxurious look, usually reserved for higher spec'ed cars such as the Lexus range. One unexpected bonus is that the trunk now closes easily on it's own when you drop it from the top due to the extra weight of the carpet, whereas previously it would require a helping hand to latch in properly.
It's certainly not the most exciting optional extra in my collection, but it's simple and effective, just how I like it