[Dinosoar]

Well, it appears a 255 square set up is good-to-go for the G42.

I just fitted 255/35-19 (Michelin PSS) on 19x8.5 wheels with an ET of 30 (OZ Superturismo LM) on all four corners to my brand new 230i, M Sport (yes, with the M Sport brakes).

I pulled off 791M Double-spoked black wheels off. Those fronts are 225/40s, so I was pretty concerned about the much larger size. (They'll be on eBay very soon)

I still need to drive it hard, but I did full lock, and jacked up the opposite corners and saw no contact, nor any "near misses."

The wheels push out more, even more than the rears which are the same size tire and wheel. I am very particular about where the wheel lines up with the body...I hate it when it looks sucked in the fender, and hate it "poking" beyond the fenders. These are near-perfect...I'd prefer a few mm inward on the rear, but they appear to clear the fender well. Fronts look perfect to me. Of course, style, wheel type, stance are all subjective. Rubbing and contact are not subjective and I think this setup is good to go regarding that.

In the fourth pic, the rears sit outward more than the fronts. Seems like there may be more room to push the fronts out, but not the back. Rears seem at max outward orientation. The big questions some may have is 9" wide wheels. ET will really matter there. I think the right ET will allow a 9" wheel up front with possible 265 fitment, but I'm not willing to buy-n-try. For now, my 255s will meet my needs.

UPDATE: I weighed each wheel. My new wheel tipped the scale at 50.1 lbs. The 791M front was 50.2 lbs (yet so much smaller!), and the 791M rear was 52.6lbs. Not much of a savings in weight as I was hoping, but they numbers are what they are, and I'm glad I did not add weight.