If you don't mind replacing it every few years when the finish flakes off, buy cheap aftermarket. I'm on my second set of TSportline carbon fiber mirror caps. They seem very high quality, but these aftermarket finishes just don't hold up. The first set finish flaked after less than 24 months. If you actually want it to last, buy the Tesla OEM unfortunately. My OEM rear wing on my P3D+ is still perfect.