According to the table published by ARC Audio, the 300.2 is much more efficient, while delivering the same power. Is this a typo? See page 14 of the below PDF.
http://www.arcaudio.com/product-pdf/KS300_24-V2.pdf
I am running four tower speakers, each at 4 ohms. I was planning on running a 300.4 bridged in stereo mode. But after looking at ARC's specs, I would be much better off running a 300.2 in mono mode at 4 ohms.
Because of the environment and lack of space between the speakers, I see no benefit to running these speakers in stereo.... Especially considering how much more efficient the 300.2 is supposed to be. This should equate to being much easier on my electrical system and giving me an extended play period.
Summary of the info on ARC's website:
300. 2 Power Output at 4Ohm Bridged: 700 watts @ 68A, Eff 71%
300.4 Power Output at 4Ohm Bridged: 350 watts x 2, @ 132A, Eff 53%
It appears that the 300.2 is more efficient at all impedance loads... Does this make sense?