I believe they'll work on any car with an OBDII port, however to varying degrees of functionality. For example, as development on the DH stopped prior to the release of the MPS 3 Gen II, there have been no updates released for that model, and therefore only partial functionality is available with the DH (I think only a handful of parameters can be read from a Gen II, which for the cost of a DH make it less of an attractive prospect for me personally).
Gen I's and MPS6's are ok because there was a DH software release for them (prior to software development on the DH stopping)
So level of functionality would be purely dependant on the car it's being plugged into
That's my understanding from what I've read.
Dan