Stock SV1K shock is much better than the piece of crap that comes on the SV650. I believe it is the same shock used on the GSXR600 (resprung of course). If that is true, I do not think the GSXR1K shock would be much of an improvement.
It's like the older SRAD GSX-R shocks, not a bad shock and like Tony said, much better than the SV650 stock shock. We do service them and can make them work even better without replacing them, click HERE