Tough to tell you which way to go? All depends I guess how much you want to spend, and what you don't like about your Turntable in its current state?
I assume your MK-IV Table ha seperate Armboard, so there is the option of a different Arm, even if VPI no longer sells the Armboards. There are Plastic Companies out there who can fabricate a clone of the Armboard, then have a competent Machinist drill the Mounting Holes, and Hole in the proper place for new Arm.
There are some who will agree,, that the HW-19 is of course a dated design, being made for just about 25 years, and as well, it of course isn't the prettiest Turntable to come down the Pike, yet still a darn good Table that IMO sonically surpasses its look.
Better Arms, Better Platters of course will net you gains, and perhaps better flexibility-adjustability.
The gains you may net may not be worthwhile though, versus the cost?
Of course, there's the little tweaks, footers, shelves, Clamps, suspension, or lack of (Sorbothane Pucks) that may cost less, and give reasonable improvements. I don't see mention of the VPI SDS in your arsenal, and that's another option?
Of course if you too hypothetically upgraded to a Super Platter, which one would hope to be an improvement, the stock MK-IV Platter can easily be sold to offset the cost of new Platter.
There's many paths, and one could even go custom, with all new Sandwiched Acrylic-Steel-Acrylic Base, and Footers, ala Aries MK 3, or HR-X, if you have the resources of a materials supplier, and a competent machinist on hand.
I almost thought of doing this myself when I did some recent Mods on my own HW-19 a month ago. Mark
