If you havent got steering lock limiters fitted you will get slight fouling of the inner wheel arch liner, just as I am with 225/45's but it is minimal and only at full lock which hopefully will never happen at speed!
Obviously with 235/45 you will get the same slight fouling or even more....even tyres of the same dimensional ratings differ very slighty from manufacturer to manufacturer when fitted.
I would not think you will get a serious problem at all, but be aware of a potential foul condition and maybe fit the lock limiters (from BMW as a kit).
Best regards David