If you want to purchase the Wired DCI for use on your iDA-X001 it will work fine as long as you use BLUE button illumination. It will also work if you use RED button illumination and do NOT use the display dimmer feature. But...if you use both RED button illumination and activate the Display Dimmer feature your head unit may stop responding to commands when the headlights are on. This is a problem with the head unit, not the DCI. I know this because I've tested the iDA-X001 using the PAC interface (the "Alpine approved" device) and the head unit still misses commands. Read on to learn more.
The Dimmer feature is designed to dim the display illumination at night when the car's headlights are turned on. If the dimmer is activated when using RED button illumination the head unit may stop responding to commands from the DCI/PAC or may respond erratically. I have 2 customers who have reported this problem when they used RED illumination. I know of 3 other customers who used BLUE illumination and never had a problem, but when they did a test and changed the color to RED they also experienced the same "no response" issue. There are also a few customers using a DCI that say they don't have the issue with RED illumination. If you do happen to have the problem it is not a permanent failure, as the head unit will again respond to commands if the dimmer is turned off or the color is changed back to BLUE.
To help resolve the issue I purchased an iDA-X001 head unit but as it turned out mine is one of the "relatively good" ones and rarely misses commands when RED and DIMMED. But is does miss them occasionally, and I discovered the fastest way to test for "misses" is to hold the VOLUME button and run the volume up or down for the full range, which on this head unit requires 80 commands. Out of those 80 my head unit will miss one or two commands, but it will ONLY miss them if the buttons are set to RED and DIMMED. When set to BLUE or NOT DIMMED it never misses commands.
I then went one step further and purchased a PAC unit and tested it with my iDA-X001. And guess what? It misses MORE than the DCI does, sometimes as many as 6 or 8 missed commands during a single run up the volume range. See this video (3MB mp4) using the PAC unit and watch for when the volume bar graph pauses on the way up or down. The first part of the video is with RED buttons (with misses), then I change to BLUE and do another test and you'll see zero missed commands. If you turn the volume up high you will also hear the beeps when the head unit misses a command (it beeps because it thinks the commands stopped and when they start again you get a beep).
I also learned that the PAC unit does not send a "clean" signal to the head unit, at least not compared to the DCI. I took these screen shots to illustrate that the DCI is definitely not sending a bad or inferior signal to the head unit. The signal should be perfectly straight with no rounded corners and the extra lines on the top half of the PAC command are high-frequency signals that were not effectively filtered out.
Alpine's response - Initially Alpine tech support said the problem was the "interface" (meaning the DCI). After replacing the DCI on both problem customer's systems (one was changed twice) and the problem remained they suggested to one customer that he change the head unit. After the head unit was changed and the problem remained, Alpine tech support told me the only "approved" interface device was the PAC unit and suggested I send them a DCI for testing and they were supposed to email the shipping information to me. This was on June 25th, and as of today (July 9) I'm still waiting for that email. I'll call them again when I get a chance and see if they have any news - maybe they never contacted me because they were able to duplicate the problem.