Yep I'm using it atm Tony, with the Bluetooth OBDKey.
Many people have been pestering the developer for some time now to add SSM support but he says he doesn't have access to a Subaru so that aspect is on the backburner for the forseeable.
Using regular ODB I can get readings for most sensors that I want; it's a pretty good app and logging is good but I am really waiting for proper Android port of ECU Tracker which has SSM support.
If you can work out the parameters for custom PIDs for things like knock count and correct then please share