UDE is an ultimate driving experience event. Sign up and attend one of these events and you get emailed a promo code for $1000 off a new bmw. Besides the national UDE event, they sometimes also have special test drive events which also quality for the 1K off.
https://ude.bmwusa.com/
I don't know much about the N63 loyalty rebate, but I believe if you trade in a qualifying vehicle with the N63 V8 engine, you qualify for rebate on a new bmw. The rebate amount varies from $1000-$2500 depending on which new bmw your purchase. They have this rebate due to some of the issues the N63 engine has been having.
There is also a bmw car club of america rebate if you have been a member for at least 1 year without interruption.