AFAIC, yes it's still immature. The current specs are v1.1, and everyone knows that everything matures at v2. I still don't want to have to deal with any RF issues though..

Yeah hijack would implement kernel devices to multiplex/demultiplex the connections. In order to maintain compatibility with the player software, it will need to move the physical serial port to a new device and pass /dev/ttyS0 through the new driver. We'll also use some challenge/response scheme to initialise this so that we don't affect anyone without the box. WRT to speed, given that most GPS receivers typcially run at 4800, raw OBDII ports at typically 10400, and player's DC speed is set via config.ini, there shouldn't be any issues, even at 115200. But with a fast PIC, we should be able to hit 230400 anyway.