I had silverstones on mine (we have a laguna 2 as well).
Theres 2 types of alloy, big hole and small hole, the small hole wheels need the bolt holes drilled out to fit the larger safrane wheel bolts to pass through. On my car they also rubbed on the front arch at full lock not where you think either. The tyre actually rubbed on the torx screw that hols the arch liner to the bottom of the wing near the outside.
As for the wheel quality. They are soft, very soft.i have straightened hundreds of them. But the next pothole they get bent again.
The main benefit of bigger wheels is you can then fit large brakes.