Well, the wider tires and the bigger wheels represent quite a bit more weight and the car itself is not "light" so the powersteering pump has pretty hard job to do to begin with. the strain is especially hard if the car is not moving and you turn the steering wheel, although I have not heard pumps fail, I can "feel" the extra load on the pump with the wider tires when turning the steering wheel without moving which sometimes is just what is needed (parking)
My personal opinion the 285 are fine, the 305s are too big especially for the front wheels AND if you have expensive wheels with 35 tires I hope you have PERFECT roads where you live without any potholes...

good luck!
(I have 4 nice looking 22s sitting in the garage as 2 rims are bend, one so severe that it is terminal and I live in NE Pennsylvania. I am kind of tires buying new rims once or twice a year plus on top of that pay EZ Pass for roads that are never fixed, this is not Florida...)