I think I'm gonna purchase the 18x8.5 Ace Moda's from wheelmax for my 01 325i and I was wondering if 235/40/18 would be a good size. Will I have any problems with that fitment such as rubbing? Is the Ace brand high quality and a good alternative to the real hamanns? And finally, should the offset be 35? Please let me know if this setup will work.. thanks a lot guys.

I would say a 35mm offset with the 235/40R18 would rub on the fender. You would want to be up around 40 to 45mm to make this work. The 235/40R18 is taller than stock also so you need a little more room.
If I can help let me know.