I would wait until you move the system to the new room in the basement before adding any more power. That will (a) let you know how the extra power will behave down there within a 30 day period, and (b) let you make a better judgement re: where to spend $$ once you get a chance to really beat up on the system in its final home.

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