Q5 18" to 19" wheel upgrade
 

My wife has a 2015 Q5 that came with the 235/60/18's on factory aluminum wheels. We now have snow tires on the factory rims and would like to put a nice set of 19" wheels with summer tires on it for the summer.
My question is what tire size and rim width will fit on her Q5 without clearance issues? Also, what is the offset I should be looking for in an aftermarket wheel?
I know I should be looking for a CB of 66.5 mm and a stud pattern of 5x112.
I'm thinking 235/55/19 but was wondering if 285/45/19 might be sportier if they fit?
Thanks for looking.