Owners of the HW-19 VPI's also use the SIMS Navcom Silencers in place of the stock springs, but they are no longer in production. However, Navcom products are still being made for other purposes, particularly firearms. Others use roller bearings (by Symposium Acoustics or Ingress Engineering), Herbies Tenderfoot, and what I am intending to get---Townshend Audio Seismic Pods, an advanced spring-inside-a-bellows isolation device.
Turntable isolation
My last turntable was a VPI HW19 MK4 .... with the springs. It's isolation from footfalls was terrible on wood framed floor. Are the modern tables with sorbothane feet better at isolating?