Well I tried it and it works...
It correctly detected the SRS (Airbag) fault code I had stored, and successfully cleared it.
The kit seems handy and robust, and very easy to use. On the plus side, it does cover additional manufacturer-specific systems (outside the ODBII scope) such as SRS and EPC. On the down side, it is stricly limited to reading and clearing fault codes on these systems, and nothing else, i.e. no testing/prgramming/configuring/uploading.
As for ODBII, it has comprehensive live data features including graphs and saving to memory (so that the info can be later uploaded to PC using USB link). But to be honset this is more relevant to a mobile mechanic, it means nothing to me...
So as a tool to read and clear various fault codes it does what it says on the box, and as mentioned elsewhere on this site when it saves two visits to the dealer it has paid for itself.. plus the dealer can't BS you.
The lack of support for w204 is disapointing though, considering that the model was introduced back in 2007. I will try and see if I can update it over the Internet as you said.
) 
