On my VPI tables I notices the biggest improvement was in the tonearms. The basic platform is good, but the the unipivot tonearm is their weak link. I tried a 12" Jelco TK-850L arm and experienced a significant improvement. The gimbaled arms that VPI offers have been reported to be a significant improvement as well.
The SS cartridges are nice, but moving to a gimbaled tonearm will make Lyra carts sing with the right setup. .