I own a 2009 S211 with original COMAND NTG 2.5 (DVD with SD card reader).
First thing is the software in my COMAND; previously version (Q4/2008 1.1 2008; 0.084.2301; BFDB0092; A1718272159; 08/13), which i updated to 01/2014 12.0 2014 12.001.2301 NTG2.5eu-Vol2.0 09/29 - went to official dealer (40€). It took 1 hour, they had to connect it with DAS online and 2010 Telematics DVD to do an update. I bought the last navigation (2014 Version 12.0 - Citruslime; Part number: A2198273759 - Europe). Put the DVD in, took about 2 hours and updated my Navigation maps without any problems. Even during driving, i also stopped the update, went for lunch and when i started the car, the update continued from where it stopped.
Here is the DVD's i bought, which i am selling again, since i do not need them anymore:
Navigations DVD Mercedes COMAND APS NTG 2.5 2014 Version 12.0 | eBay
I am experienced ebay buyer and not seller, so cannot set it to sell to other countries...but it is not a problem to do so
Just in case if someone needs it, since the price for new is almost double.
The other thing i want to point out is the DVD in motion function. As everybody knows it is not possible to do so on NTG 2.5 COMAND...untill now
I don't want to brake any rules, but found the site DVDINMOTION.COM, where it is advertised that there is a software solution to get the DVD's to work while driving (advertised only for NTG 4.5, but also possible for NTG 2.5). Tried it and it really works! You send them VIN and they send you download link. You unzip the files to SD card, put it in for 3-5 minutes, remove the SD card and put the DVD in...you will not believe it, but the DVD in motion works, every other function of your comand is intact.
Even the navigation works perfectlly - since there are some solutions where you put some hardware modul to trick the car is not moving, but navi is not working.
It is not cheap, but it is really fast and easy solution, and my kids love it...TOM&JERRY and HELLO KITTY on the go all the time
Here is the video i made...just to show you that it really works.
And here is the link from my country mercedes forum, where you can see some pictures i uploaded...:
Mercedes-Benz Slovenija ? Poglej temo - Moj novi E 220CDI T in navigacija COMAND NTG 2.5
I know guys that it is dangerous and stupid to have DVD on the go, but my kids love it, and i do not like cartoons, so my eyes are still on the road