You can not bolt up rear 9.5 pp wheels ( or equivalent) on the front of a s550 unless you use at least a 5mm spacer. It is a tite fit with 275s but with a 5mm spacer it is possible.
There are a few 10-11 inch wheels that fit the front without any problems. I’m just saying that the stock wheels don’t just bolt on.
A 9.5” Pp rear wheel will need a spacer to fit and a 11” rear wheel will hit the fender.
another problem is if you lower your car it pushes your wheel and tire out even further. My car is lowered 1 1/2 inches in the front and with the caster camber plates installed the wheels are dead even with the fender. Any wider or any lower it would be sticking out