The final cut of the 8th episode of the Tesla Motors Club Podcast, featuring Balazs Biro, of the prominent Hungarian EV channel Villanyautósok, is now available. You can watch it now on YouTube or listen to it on all major podcast networks.
The CAN bus is available at the diagnostic connector in the passenger footwell, but the product you mention is designed for the Model S. The CAN messages are different in the Roadster, so you would need to be able to modify the firmware in the controller of that device (or get the manufacturer to do that work given details about the Roadster CAN bus messages).
The CAN bus messages in the roadster are different than the Model S. The manufacturer would either need to modify their product to support roadster CAN bus message format, or you would need to build and write code for a convertor box to modify the signals to match.
The publicly available info on roadster CAN bus messages (instrumentation bus) is here: