Are SLR Balanced inter-conect's better than RCA 's

I have a Sunfire Theater Grand II pre/proc and Sunfire Cinema Grand II amp (225 wattsx5). Will the blanced inputs/outputs improve the sound quality enogh to HEAR not just MEASURE a difference ? Also,is it OK to use the available 225 watts to drive a quality speaker rated at 80 watts RMS(4 OHMS resistance)so long as I keep the system at a non-clipping volume level.