Agreed, I'm on a +30mm, rim width really doesn't matter, if anything the 10.5's will fit better as the tire will have a slight stretch making the sidewall "shorter" compared to my 9.5's. I'm just basing this off looking at my 255's. It's damn close and I'm sure I can work the liners if there does happen to be some slight rubbing. Obviously suspension set-up will be a factor too.

well those are 18x10.5 +43, unmodified factory fenders and liners

which means you could then instead do 18x11.5 +30 with a 285/30 and be where the inside of my wheel is and the outside where your wheel is along with a wider tire between the two.

That’s aggressive and why I poke fun at people who take narrower wheels and tires just to place them outboard with a low offset and force themselves into rolling fenders and such. If you’re going there, just do it right in the first place. Otherwise it's not aggressive, it’s posing.

lol...

https://cimg4.ibsrv.net/gimg/www.rx8...35f3da945e.jpg
:Peace:

Some of them looks like gangsters from yakuza lol