Thanks for the reply
I'll give Pioneer a call today and see what's what, hope they're helpful (and know what they are talking about).
I'm also trying to get to the bottom of what my HD3 is the equivalent of, I'm guessing it's the Z2. After reading the threads on here re: HDD unlocking and (particularly) the Z3 image it'd be good to know whether they'd work on my unit too. There seems to be also zero 'enthusiast' info on the HD3