Thanks for this CanadianDriver! I understand more now; still learning though.
To my setup on the front, it is 255/40/19x8.5 with +30mm offset. BMW 225M wheels on M Sport is 225/40/19x8 with +37mm offset. Go to this website and enter the data:
http://www.rimsntires.com/specs.jsp
the result shown the backspace of the wheel is 1mm different only and the tire is 8mm closer to suspension; but stick out 22mm farther. The scrub radius maybe off but I don't think it's off that much? One thing for sure is the wheel package have enough clearance from the suspension.