If your friend believes she has mono, she should go get her blood tested so that it can be determined whether or not she has it. Everyone reacts to mono differently. Some people get mono and they feel like they have a sluggish flu for a month. Other ...
You really need to know the RMS for the subs. If you don't then you might not provide enough power to the subs to make them work to their full potential or too much and blow the speakers.
ok, that last answer totally blew my mind... dual is not a quality brand, and you need a MONO amplifier for subwoofers, not a 4 channel. A 4 channel is ~65% efficient, a mono class D amp is around 80% efficient. most 4 channel amplifiers do not have ...