These unique mirror caps are skinned in genuine carbon fiber, and were found on the one-year-only, Japan-only special edition 2018 WRX STI RA-R. Besides being made of carbon fiber, they also feature aerodynamic fins to guide air over the top of the mirrors. They install directly in place of the stock 2015-2021 STI mirror caps. Yes, they are very expensive.

Set of two carbon fiber mirror caps, left and right. Imported by us from Japan.

Fits all 2015-2021 Subaru WRX STI. You could also install them on a 2015-2021 WRX if you installed the mirror turn signal indicators.