hakushondaimao
Headphoneus Supremus
I assume the stacking kits don't work with cases?
Pretty sure you're correct about that. The good thing though is that the X3 2nd generation's amplification is so good that for most portable uses, you won't need to stack it with an amp when on the go. That's one of the main reasons I jumped on the 2nd gen. so quickly, even when I was still enjoying my 1st gen: pocketability!