I was very close to making the same decision you did. The 235/45 were cheaper, in addition to having better snow properties.

I have the M3s as well, but ultimately decided to stick with the stock size. I decided I didn't want to deal with differing rolling diameters, though it would have never occurred to me that the small diameter difference would cause rubbing. I have no issues with the same tires in the stock size.

Good luck finding a solution.

 

I'm just curious as to why mine are rubbing, since they're the same size (245/40R18) as the stock Advans. Only difference I can find is that the Pilots are 245/40ZR18 instead of 245/40R18... what is that extra Z for?

 

Z is for 150+ mph tires. Stock A13's are Z-rated Y.
Manufacturer's have slight variations on tire size even though they may be the same spec due to differences in tire tread, pattern, people and tools used to measure them.

 

According to the Tire Rack, the Pilots I have are 1/10 of an inch larger in diameter than the advans, and they seem just a shade wider where the "corner" of the tire is, having a rounded edge where the advans are a much more squared design. I think this little extra roundness combined with the tiny increase in overall diameter is enough to cause the rub even though the tires are the same "size" according to their respective sidewalls.

Took the Evo in for her first oil change (I always get one at around 1500 miles to get rid of the "break-in" oil... not sure why) and showed my tech where it's rubbing. He checked for signs of any damage and found nothing wrong, and said that it's just barely touching when the wheels are allt he way cut, and because of the angle of the louvers it's hitting, in reverse (usually when my wheels are cut that much I'm backing out of something) there's no chance of it being anything more than an annoying sound, so I'm not worried about it anymore.

 

already took care of rubbing lol its so easy. Take the wheels off look for the prints of rub and chop it with a saw since its just plastic. I made two 2" X 3" holes and its all good now.