Most recent broker ads are around 16-17% for 330xi so 10% seems very poor, especially since you are being penalized around 3% for the mileage. new 330xis are being discounted around 11%, so that could be better option.
I believe it’s $3K for lease cash and loyalty, but could vary in different parts of the country. On that note, markets with limited competition can be difficult to get the higher end of the discounting seen here so may be worth traveling.
Look at any of the recent deals to understand specifics of the deal structure, like this one: