Mine is all hooked up now. The sound quality is excellent with the Imprint processor plus very high end speakers and amps. However, like you'd except, the source material on the iPod/iPhone has a huge bearing on the overall sound. I will probably buy an iPod just for the car and re-rip everything in my collection to lossless AAC to make sure things sound as good as CDs. With lossless encodings this setup rivals or surpasses the Eclipse CD8053 that I had previously.

dn7309, you cannot use the iPhone when its connected. The screen turns white and there's a graphic with a message like "Accessory Connected". That's another reason not to use it with an iPhone, given the choice... I'm not sure that you can receive a call or text while it's plugged into the full speed USB cable.

The knob can fit fine with radio door closed but the shop that did mine had to create a custom bracket for the HU so that it could sit further back. They said it was an easy dremel job.

I got the standard Alpine dash controls from PAC. They do work with this HU but the controls are sort of temperamental. The volume toggle works well (though there are so many minor sound volumes that you have to hold it for 2-3 seconds to hear a difference) but the other buttons are slow and sometimes don't work. The button above mute was programmed for the fast forward button but it doesn't always work and you have to hold the button for 1-1.5 seconds for it to register but not 2-3 seconds which causes the track to fast forward.

XM works okay but the sound is as awful as usual . Apparently the wiring for Imprint + XM is quite complicated and requires a call to a level 2 Alpine tech to get it right. (It's not a daisy chain, but something more like looping back through inputs and outputs of the various boxes in one specific order).

I'd recommend anyone that buys this deck and wants good sound quality, as opposed to just wanting good iPod navigation, to get the Imprint processor. Even with the boosted outputs with Imprint, there's a huge difference between the microphone and software tuned audio curve to what you can achieve with the parametric EQ. Without Imprint, I probably would have immediately replaced the deck but with it I'm very impressed.