I'm new to the world of MB tuning, but I'm tryin to help out a friend. I know staggered front and rear wheel widths are common on the MB vehicles, but is staggering the wheel size common as well (ie. 18' in rear and 17' in front). My friend really wants to get the BBS RK II wheels, but they only come in 17x8 and 18x8.5. Any feedback would be appreciated.