The NAT AA12s Stereo Controller fitted in my Raven 2 works exceptionally well. I also had factory fitted Bose Lemo plugs. Music via the aux socket to iPod is perfect.
Did I read somewhere that Robinson WILL NOT accept responsibility/suitability for any other after market fit for compatibility ?. One thing to note about the GMA340 is that this is primarily for the fixed wing market and the P1 and P2 positions (volume & sq) will be the wrong way round, so to adjust P1 you will go to the left of the panel as opposed to naturally going to your right. (R44 P1 right). When fitted to the Enstrom its OK because P1 is on the left.