Anyhow , gajagfan & TedW clarified the issue confirming the indication from JeffInDFW that indeed a different transmission is key to the improved times. The more aggressive diff and the rest of the changes already discussed here make up the story.
Why do you say it's the transmission? It's the gearing and to be honest the only place the gearing makes a difference is in fourth gear since it's direct drive. The gearing inside the MM6 is different from the M10 which makes the gearing the same in pretty much all the gears except fourth. It has an effect, but less of an effect than putting in 3.91's and keeping all the internal ratios the same.