I've a pair of these for monitoring on stage in a band situation.

TBH, I wouldn't use them for FOH. They deliberately (because lows for monitors is not a good idea!) have next to no lows, and aren't really flat by any stretch of the imagination.

I doubt they will sound better than the built-ins on your S950, but I'll be interested in hearing your experiences.

Unless I added a small sub, I wouldn't use mine, that's for sure.