I just took my 2018 M3 out for a test drive with 10.4 FSD beta. I frankly don't appreciate any consistent improvements with this newer vetsion, having lived with 10.2 and 10.3.1. Any change I think I see could be imagined, Elon had stated unprotected left turns were better in this version, but I am not sure. I can make the same left turn repetitively with it being hit or miss. Regarding Rt turns, I found my car in the center of an unmarked residential street at a stop sign waiting to turn Rt and not providing enough room for other cars to turn Rt into the road from which I was exiting to turn Rt. This behavior was not seen by me in earlier versions of FSD, yet others have reported this before. What makes it difficult to judge changes is the inconsistency of FSD. Unless there is a dramatic consistent improvement or regression is difficult to for me to be sure its better or worse. If others are certain they see changes in 10.4, better or worse, real or imagined feel free to post your experiences.