I've got the MKi9000 connected to the RCD300 in mine.
The default is that the mki plays through its own amp, not the headunit. (so you don't actually need the headunit on when streaming) Sound isn't the best, and the volume is limited!
I've got one of the aux-in boxes that imitates the cd changer, and have switched the mki to play to its aux-out instead. Sound quality massively improved, and can get the same volume as cd/radio, plus volume via mfsw and Gala at speed.
Even set up like this, calls/texts still play through mki itself, so whatever source you're listening to, the headunit switches to phone.
