I've always hated the red rear turn signals they put on US-bound cars. One way to restore the original European look would be to purchase Euro-spec lamps, but that would run you around $700-800 each; cheaper with used from eBay, but still expensive.
Another way is to put amber LED bulbs and code the car to not throw a code. Just tried that and the result is better than I had expected. Perfect amber illumination even though the lens itself is red.
The bulbs are WeissLicht Spectrum, $89 a pair:
https://www.bimmian.com/WeissLicht-L...for-BMW-E70-X5
Coding can be done using a BMWhat App with any compatible WiFi OBDII dongle.