It's a 2009 GT500 w/Shaker 1000 setup. Might upgrade speakers later, but for now, just head unit... Liking the D9 so far, it's nice and snappy for the most part. Runs awfully hot. Wireless Android Auto (and I think Car Play but N/A to me). As for the massive POP at power on, I checked the remote/amp-signal wire, and it puts out 5v like you'd want for these cars. BUT, the problem is that the amps are switched on the moment the key enters the barrel (albeit off again after 10 seconds). Thought about putting a delay in that circuit, but if I don't start the car within the three seconds or so, it'll still do it. AND THEN, after shutting the car off, the system keeps everything energized for 20 min! And it's not like it's on and able to be listened to, just off but still consuming power! Amp too. Gonna kill the battery. Talking to support, because this seems like it would affect every single D9 they sell... Plus, sucks that it doesn't at least keep running like stock up until you open the door to exit the car. There's the plug/harness that sends a CAN signal to the stereo to tell it when to turn on and off, just seems like it should be able to use that to either start a power-off timer, or monitor door_open and shut off then. I digress...
One possible solution to the pop, if they are unable to help, is to use the extra aftermarket amp 12v remote wire which is ONLY switched on after the stereo starts up, and put a resistor on it for 5v. It comes with the added benefit of killing the amps as soon as the stereo is off, not the 20 min wait.
Let me know about the wheel buttons. Any idea what those blue and yellow wires were for? Thought about grounding the blue, as seen in a PAC tutorial (can't hurt, right?), and then possibly combine the yellow wire with the purple wire, and if that fails, the second wire in the Dynavin connector (though that might just be ground). Have you tried either of those?