Naturally... I'am still flabbergasted with so many adapts tring to sell RWD as superior to AWD! I accept that RWD is better than FWD, but it can't be better than AWD, certainly not in a balanced BMW! And be prepared, the future for high output will be AWD, I have no doubts.
1/ for the extra weigth, AWD only brings little extra and the weight is positioned favourable for the center of gravity.
2/ for efficiency losses, AWD is almost invisible.
3/ for vehicle dynamics either.
4/ for the extra cost of 600€, what... are you really not considering it!?
again, M135i AT has to be AWD. no excuses. When you don't order it like this, take some time to council professional help?