I would like to upgrade the wheels on my 2008 X3 (E83) . The purpose is to use the stock wheels for snow tires next winter. The car came equipped with 17 x 8 wheels with a 5 x120 bolt pattern and 46mm offset. The tires are 235/55 x 17. My hope is to use a stock wheel (18 x 8, 5 x 120 bolt pattern) from a more recent X3 however I noticed the newer wheels have a 43mm offset. Are the wheels interchangeable ?? I am also hoping that installing 235/50 x 18 tires as offered as an option in 2008 will not effect the accuracy of my speedometer/odometer. Advice appreciated.