I assume the Dice "not a DIY" warning is one of those standard blanket warnings; it is no easier or harder than installing the factory switch box. So yes, it requires disassembling the console; etc (the Mazda instructions tell exactly how to do this).
Everything connects to the Mazda wiring harnesses, headunit, etc with proper adapters. There is zero cutting so it could all easily be undone.
It took me about two hours; but that was because I was very slow and cautious having never opened the CX-9 console before. I think I could do a second one (switch box + Dice) in about 45 minutes.
The hardest part for me was figuring out exactly where to position the Mazda switch box; the Mazda instructions are really good, but not 3-D

The Mazda wire routing instructions make the switch box a no-brainer and result in everything nicely secured. Minus the switch box; the Dice-to-headunit wire alone would easily route from the headunit to the glove box without complication.
I routed the iPod cable out of the glove box per Mazda's instructions for their iPod kit. This works great for the Dice. The Dice is so small and light that I just left it in the recess behind the glovebox next to the fuse box. This means I can just pop the panel out of the back of my glovebox and disconnect the Dice to reset it's DIPs, etc (it also has it's own aux input that could be used from their too; but unnecessary since the CX-9 has aux)... also easy access for upgrade if they eventually have good news on the Playlist display issue.
The iPod cable stays in the glovebox when not in use and I route it out the lower left side of the box when in use. The glovebox closes easily and I leave the ipod in the little dash box below the headunit.
Here's a link to the relevant Mazda instructions:
http://www.mazdas247.com/forum/showpost.php?p=3624990&postcount=7
Also; it's clear from the Dice Electronics site but not from some online vendors; you need the "i-Mazda-R2" for text and CX-9 not the older "i-Mazda-R" version.
-Jeff