Yep, MV2's (135M's) were standard fitment to the Z4 Sport model (2006-2009), mine came with them
Edit, The 3 series (E90) could be fitted with the 225/40/18 all round and they may come from that model, but as previous post states that the zed came with a staggered set up so 255/35/18 on the rear on 8.5J ET50.
You can fit the 225's all-round if you wish, but most think the wider rears look better