SDS or phono stage


I have a VPI Scoutmaster with Soundsmith Zephyr Mk II cartridge, jmw memorial arm, a stainless steel vpi record clamp, playing through a Musial Fidelity KW500 integrated amp with on board phono stage. Sounds quite good, but my question is this: would I be better off at this point adding an SDS or an outboard phono stage? Or both? In what order? Thanks!
arsh
Thanks everyone for the useful information. I got a bit of an education there. Mcbuddah, thanks for the tip about the ECPA. I had not previously heard of it.
At least now I know that I can blame autocorrect for converting my moniker to "Lewn". No one should think I am at all angry about it. It's been happening ever since I started posting under "LewM" on Audiogon. I find it amusing, in fact.

Arsh, from all I have ever read about it (and that's all I know about it) the Herron phono stage you have purchased will likely make you very happy for years to come. I think you've made a good choice.

Thanks, Al.
Thanks again. I hooked up my sds and set speed using the kAB. Question: do you leave the sds on all the time and turn the turntable motor on and off, OR do you leave the tt motor on all the time and use the sds to turn it on and off? Thanks again.
Motor always on, and use the SDS to control the on/off. If you do it the other way, the SDS will not start at full power and then ramp down.
Thanks. When I was setting it up, I watched the sds as I turned the motor off and on. When I turned the motor on, the sds voltage jumped to 115 then down to 72, as I gather it should. Do you really switch the sds on and off every time you flip the record, brush it clean, etc?