I have a similar question. I have two systems setup in my house.
system 1= HK AVR 630, Onkyo DVP..., L/C/R Paradigm Titan Monitor (V5 series), Mirage 10" sub, and JBL 6.5 in-ceiling surrounds
System 2= Denon 3805, Denon 1930CI DVD Paradigm Monitor 11's (V4), CC390, Titan Monitor (Rears), and a PW2200.
Issue: Smaller systems sounds dramatiaclly better than the larger (speaker size, and cost) system. Rooms are different; one is a bedroom (small system) and the other is in the basement.
Q. Do I need an amp on the larger system to improve the SQ or is the difference in performance purely room acoustics.
My real question is: Is it better to acoustically treat the room or add an external amp. I plan on running some Sonnace in walls for the rear once I get long enough speaker cables.