There was a US promo video a while back that seemed to show the upper (brake) lights being used for turn signalling, rather than the lower amber lights as in other markets. But it was very brief. That seems to be confirmed in this video of the US spec car at the LA auto show. Opening the trunk flashes the upper brake portion, not the lower amber lights like I've seen happen in reviews from other markets. 😔 Hopefully the lights are there, and could somehow be enabled like you can typically do on Audis with VAG-COM editing.