Thank you RICHARD V6 for supplementing information, moreover in the m3w 5 speed there were two types of teeth 1/2 the first model of teeth was much more inclined (2012) because in 2013 the teeth were larger and less inclined and machining a bit rude. It also seems to me that the crown gear pinion ratio for the belt transmission is 1/2 corrected by the number of teeth of the belt.
