How did you detrimine they are 2.7 ohm speakers?
Do they say that, or did you measure them with a VOM?
If you measured that, that's not the impedance. That's the DC resistance,
Even though they are both stated in ohms, there is a difference. Impedance is more frequencty related and is moreso calculated from several other figures than measured with a meter.
But in either case, I'd guesstimate their impedance is more like four ohms, which is still asking for trouble with that, and many other, receivers.