How big is your room, how "spread out" is your system (eg. how many feet from the main speakers to the listening position) and what do you listen to the most ?

More to the point, what would you like "more of" ? You have a pretty nice, well balanced system there already.

M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8