That depends on whether you want to stretch tyres... you could get a 17x8 on easily if you wanted to stretch a 195/40/17 over it.
You can get 16x9s in the back by stretching a 195 or 205 over the rim but it's a big stretch - not at all uncommon, though.
It comes down to whether you want performance or looks, as an imperfectly seated tire is hardly going to love side loads if you're ragging it around corners.
That said, many BMWs come stock with stretched tyres, which is interesting in itself.