I was actually on that drive w/ Sergio, and I had the same issue. We talked about it briefly but were both stumped by it. I do not recall seeing the DSC light ever illuminate, but it is possible that it flashed, and I was too busy driving to notice.
I do have the tech package, Mdrive, etc, and while coming through the turn I felt the computer kick in and rob power to the wheels. It was a considerable shock considering I was under the assumption that I had told the computer to go away using my Mdrive settings. What is pretty bad is that it sorta unloaded the suspension in mid-corner. Not very good. On the return trip I put the Mdrive to MDM mode and I didn't feel the power cut-off at all!!
That being said, I was not able to fully replicate that on subsequent turns. We can't be the only 2 guys that this has happened to. I mean, what would the odds be of 2 2008 M3's having the same issue, on the same morning, on the same roads, being the only cars with the glitch.
Now that I just read my post, I wonder if we had this issue on the same corners. If that is the case then maybe
it somehow was a road surface issue.....