I guess I am still dwelling on the same question. Do you see any SQ based justification for getting the HD over the PDX? The other way around? I do kind of like the idea of plugs but they're not worth paying THAT much more.
From what I have read so far, the only issue is the 2 ohm volume levels, which should be easily fixable by reducing gain sensitivity using the MS-8 hidden test menu to level match.
FS:Sub Amp - works w/ Technic harness! MRD-M300 - cheap