I am using LS60s with CAT6 (and S/PDIF) in and CAT6 between the pair and do believe that there is any reason to entertain "upgraded" or "audiophile" ethernet cables.
In a large room with many reflective surfaces, the DSP in the LS60 will probably not be sufficient and that capable room correction will be necessary, as with any other loudspeaker. I would also suggest supplementation with at least two small subwoofers to (1) enhance the dynamic performance of the LS60 and (2) deal with modal acoustic influences. Again, the latter suggestion applies generally.