16/2 wiring, in a non-critical location should present no issue whatsoever. It is more typical to see 14 gauge wiring (14/2) The first number is the gauge of the wire, the thickness. Over longer distances you want thicker wiring, which means lower impedance, which means better sound. Thicker wire has a smaller number. So, 16 is thicker than 18, and 14 is thicker than 16. In home theater use, many people use 12 gauge or 14 gauge to preserve all the frequencies that are being presented to them. But, I have personally used 16 gauge wiring for long runs in non-critical listening locations with decent speakers, and couldn't discern any difference between that and using 12 gauge wire which I temporarily ran to test audible differences. Typically you need a good room with good acoustics and good equipment to start noticing those types of details in my experience. The 16/2 wiring in place will be fine... Now, whether or not the Bose speakers are any good is a completely different question. Worth researching Bose instead of just reading their marketing literature. What size are the drivers in the speakers you are using? What is their sensitivity? What was their cost to that of comparable models from other manufacturers?