The GPS is neither expensive nor unsupported, it’s not available YET. The original unit was 8 channels but we now have 12 channel units that will be available at launch.
There is support in the form of a library written by Spiv for anyone to use. And there is software written that uses it. http://www.cs.helsinki.fi/u/jikorhon/condev/gp32/
The Bluetooth is a similar story just a little behind the GPS unit.