There is a thread a little further down in which Stephen735i states that-
The total number of 550i/6mt F10 is 611 cars with the following details:
2011: 424 cars
2012: 90 cars
2013: 97 cars
I really doubt that there are hundreds for sale at any given time. There were only 269 with the Msport package and my Carbon Black Msport with 6mt is one of 89 ever built. It doesn't make it worth any more money yet and the miles I put on it will prevent it from ever being collectable. I'm willing to give it up for the right price if you want to "save" it.
BTW- they stopped producing the 6mt in the 550i in 2013 worldwide and are not expected to resume building them.