I would think the most cost effective upgrade path would be to trade it into a dealer for a VPI Aries Scout. You may want to e-mail VPI with this question.
You can get the parts needed for an upgrade to either the HW-19 Mk3 or Mk4 directly from VPI, or from a VPI dealer. The upgrade will include the laminated acrylic/steel plate plinth, 4 spring suspension units, the heavier acrylic platter, and the spindle/thrust bearing needed for the heavier platter.
I think there is an ad currently running here on A-gon for the parts needed to upgrade to the Mk3 version. I have had the Mk3 version, which I eventually upgraded to Mk4, and there was an audible improvement. The VPI HW-19 Mk4 turntable is one of the real bargains in high end analog playback -- a LOT of turntable for the money. Personally, I would pick the HW-19 Mk4 over the Aries Scout.
I started out with the VPI jr and upgraded to the mk3 and now to the mk4. As Sdcampbell stated, the improvement in sound is very obvious. I would keep your TT and work on upgrading to the mk3 and then the mk4 when you are able. That is the great thing about this TT. You can upgrade as your wallet allows. The upgrades are easy to do also. If I can do it, anybody can. I also had the PT6 tonearm. I upgraded to the VPI JMW Memorial 10 and the improvements were huge! This is a wonderful tonearm, but I would not get it until you upgrade the TT. Enjoy.