I use my LS60 as LS/RS in my surround system and send the S/PDIF (via the AES/EBU outputs of my HAPI II). This runs from Jriver (with Dirac ART) and, using the channel routing options of Jriver and Merging's Aneman, LS60s (and/or other speakers) can exist comfortably in a multichannel system beyond 8 channels.
As for output levels, the addition of subwoofers not only extends the frequency response in the bass but relieves the 4 "bass" drivers in each LS60 of the demand for power output at their low end, permitting higher SPLs. Of course, simply going multichannel helps, too.