Mtrot? I jest of course (unless u were Zd542, in which case u deserve crucifiction!! :-) ). Glad it's sounding good for u of course. (U do get more dynamics , quieter noise floor n better separation, usually, n more refinement n such w better pre's. That's all. .when ur ready)
As for this guys Receiver options, again, im recommending the biggest baddest latest piece he can find at ur max budget , then also make sure features you just cannot live without are included n great if u can get a warranty!! (Yup n id make sure room EQ).
Good luck