Originally Posted by jphughan
I talked to a tuner who knows how to modify (not just remove) the top speed limiter, and he said that the stock limiter setting is either 174 or 184, can't remember which. I haven't tested that myself, but that's what I've been told. There's a thread on here asking that question and a bunch of people gave a bunch of different answers, so maybe that's what you're thinking of?
See this: http://www.bmwusa.com/Standard/Content/Vehicles/2012/M/M3Coupe/Features_and_Specs/M3CoupeSpecifications.aspx
Top speed limiter is at 155. I've experienced this on my E92.