If OEM then likely to be 8" wide with 34mm offset all round or 8" / 34mm at the front and 8.5" wide and 39mm offset at the rear. Either way, E9x offsets are more aggressive than F2x series so unlikely you'll need spacers.
Link below is a useful website to check oem wheel spec's
http://www.alloywheelsdirect.net/bmw...ies_e92_alloys