Ive seen guys run 19 x 10 ET 40 w/ 275/35 in the rear successfully but they are on coilovers. you may want to wander over to this thread
https://f30.bimmerpost.com/forums/sh...1166496&page=9 give you some better options. Also you want to keep the rolling diameter less than 1% on your tires right now you are at 1.2 % with those two tire suggestions so that could potentially lead to transfer case issues if nobody has told you about this yet.