I have an E46 coupe on the way. I am either going with 18's or 19's. My question is with the width. If you get a 8.5" wide rim, should the tire be 225 or 235? I see it both ways around here. Also, I noticed both 18's and 19's are taking 235/35 tires with the appropriate diameters. So, since the sidewalls of the tires are still 35, does the ride differ between 18's & 19's? Also, do you have to get any speedometer changes if you put larger wheels on? Thanks!