Re: 2-ohm 200 watts rms 6.5 component set
The JBL P660C has a sensitivity rated at 94 db (2.83V@1M). My Boston Pro's are rated at 91 db (2.83@1M). So, all else being equal, the JBL's will be the same volume, with half the power. I bought a set, recently. I plan to give them a test listen in the next month, or so.
Generally, higher impedance speakers are more efficient....but, that's NOT a hard and fast rule!
The Top 50% of income earners pay 96.54% of All Income Taxes. The Top 1% Pay More Than a Third:34.27%...so, the next time you hear about "tax cuts for the rich", remember...those are practically the only people paying taxes.