Sorry, it's been a while, lots of stuff going on.
I ended up ordering the 18" 397 through a friend who will be importing it along with 18" runflats that are specified for the F30. Taking delivery of the car in a week and the wheels should be here by then, so will be fitting them on before it rolls out of the dealership. Only thing is to find a buyer for the brand new 414s coming off the car or getting the dealer to take them back.
PM me if you want share contact info and/or want more info on the price or details on how I went about it, etc