I currently have the RP-600M for my L/R front speakers. I have the SVS SB-3000 on the way for my sub. I will eventually get the RP-504C or RP-404C for my center. I am not sure what to get for the surrounds yet. My room is 12ft x 26ft with 8ft ceilings. I use it 50/ 50 for movies and music. I have a Denon x2300 amp. My question is: Should I upgrade to the 6000f and move the 600M to the rear? Or will I be happy with the front 600M's for the fronts? What would you recommend for the center and rears?