I've got 18x9 rims on my car,and let me tell you,those were pigs to get under the car.
You can of course resort to rolling the arches and all sorts of other mucking around,but it depends on whether or not you want to do that to your car.
We did it to get 245 section tyres onto the car,and needed adjustable topmounts at the front,to get sufficient camber,and the car runs 2.5degrees of negative front and rear,which is OK for what I want,but not ideal for most.