Remember that bigger tires also equals more weight, more noise, more rolling resistance. Unless you are supercharging, the stock set-up is just fine. It would have been very easy for BMW to put different sized tires on the stock car but they didn't. There is a reason for this.
If you are supercharging, 275/30 & 295/30 is a great combo, other wise the stock tire size and maybe up to 255/35 & 275/35 is optimal.... No extra weight, no extra noise, a touch more sidewall for added comfort and no fitment issues whatsoever under any circumstances.
Just because you can fit bigger tires, doesn't mean you should. Tires that get too big for their intended purpose also start to look a little ricey.
Audi S6 * Audi S3 * Porsche Cayman GTS
--Former BMW M3 owner