Need immediate help

To those who responded to my earlier thread asking for 2k linestage recommendations, I had already sold the c-j when I posted. I have taken the (gulp) SS plunge and got a Pass Labs X-1. Question for Pass gurus: must I run balanced; do any of you run single-ended? If I do run single-ended, what would I give up? (I have tried getting info from their website but it is vague).
Secondly, do any of you use amps other than Pass, and which mate well with X-1, or other Pass linestage/pre; I'm looking for something high current, at 150/watt/side. The reviews I've read of the Pass X150 hint that it may be a bit "lean" in the midrange?
Thanks for the info, in advance. Happy Holidays!