Currently I'm running a pair of Aleph 2 mono blocks, and I have heard and audition the Pass X350. And I can defintately relate to the feeling that there maybe some lacking in the bass with Pass Equipment when I first aquired it, but after listening to my whole CD collection, switching in and out components such as a friends Krell Amp. I found it was not the Pass that lacked anything, more so it was other equipment making up for there deficiency by adding(for no a no better way of putting it) bass or bass slam as my Krell owner friend says. Now I'm not picking on Krell I do like there stuff but it was the only class A amp I switched out and listened too. But I feel my friend prefers the bass to the Detail and soundstage that a Pass amp brings. That's why there is more then I amp maker.
Now as far as cables, I had AQ, then I went to Tara, but found a medium with XLO switching to them gave me a fast low end. That seemed to work well with the Pass( I think XLO is know for a bit of coloration on the bottom and it worked for me).
So to wrap my experience up, and listening to my CD collection a million times switching stuff around. The Pass Equipment did everything right(or the most thing right), it put the bass where it supposed to be and not were it wasn't and that took alittle getting used to.