The differences, although noticeable, are really subtle (with the exception of the front and rear facias). Saw one on I-5 in Southern California last weekend just over the Grapevine and followed it for about 10 miles. Had New Jersey plates, and was the Modern Line in Mojave Metallic paint with the 19" double spoke (401) wheels. Looked very nice on the road.
Past: 2008 M3 (E93) naturally aspirated V8 realness!
Past: 2012 740Li (F02) M-Sport (European Delivery)
Present: 2016 750i (G12) M-Sport