Just to let you know how low it can go: Got a used BP6 from Ebay Germany with two 366s that are guaranteed to run @550 and Neolec coolers for only 64$- including shipping!
I have absolutely no use for this yet but I love my BP6... and the caps seem to go bad (some are bulky)... besides I can´t get my current setup to run @2x 550 (stuck @523, no too much of a difference, though )