Certainly you won't mistake them for little cube speakers.
Still, if you assume a 4 ohm nominal load instead of 8 ohm nominal (not altogether undeserved given the actual minimum impedance), you're dropping sensitivity per watt by 3dB; so when you go to an SPL calculator such as
Peak SPL Calculator , instead of 100dB, you pop in 97dB. With 20 watts into 4 ohms at 10 feet, suddenly you're looking at 100dB instead of say, 107dB if you assumed 50 watts per channel into 8 ohms with 100dB sensitivity w/ 1 watt.