Well, I wouldn't even be allowed to run anything wider than +15mm on each side. Here in Switzerland it's only allowed to put wheels (or spacers, but for spacers there are even more strict regulations) which widen the car by 1% on each side. The Levorg has a wheel gauge of 1530mm which means I can go for a maximum of 15.3mm on each side. My +40 tires are nos almost exactly at the maximum.
When showing up at the roat traffic licensing department they alreay initially said I can't use those wheels, but then checked again and it was exactly at the maximum allowed range.
Sure this might be different in your country. I know in Germany they are also pretty strict and need to have the tire width being approved with your wheels too. My wheel manufacturer also writes in the general approval document, that you need to modify the rear bumper for 225 wheels and even more modifications for 235 wheels. Here in Switzerland I just modified the latch I referred to and they just went on a test drive trying if anything scratches. If it would, then they don't give approval. But it didn't in my case.
But it's interesting you could even mount 255/35/R18 with 9.5inch and 45 offset. Impressive.
Same rules here. Everything need Tuv approval if it's not original. Carbon fiber hoods needs Tuv too. We follow eu-regulations, even though we are not in the EU. Light bar, air suspension, wheels, and most other things on my car is illegal, and needs to be removed when the car goes to the 4 year checkup (then bi-yearly), or the "TÜV" stops me and asks "nicely" to have a look at my car.
Sweden, wich is a part og the EU, does not have the same rules as us, and does not need Tuv approval.
The tires fits, rubbing wise, but the front ones are around 5 mm on the outside of the car, and would not pass the inspection even with tuv approval.
We are not allowed to change the track more than 15 mm together (7,5mm on each side), and the same goes for spacers, and the spacers must be bolted on, and would need Tuv approval.
The tires needs to be within the limit that STRO says, so so a 9,5 inch rim the tires would need to be between 235 and 265 or so.
So, 255 on a 9,5 inch wheel won't give give you rubbing on the Levorg, but it is not by the book.
I know a guy in Sweden who runs 19x9,5 et42 with 225 tires, coilovers, and as much camber as me on the front, and i guess it does not rub much either.