Generally speaking, the the thing to get right with fitting internals to your existing pump (eg Autotech, VIS) is doing a clean and clinical install. Failure is more likely to occur if it’s not done properly. Obviously with the full units like Loba or APR the install is already done, but you pay a price for the privilege.
I believe Nick and co at R-Tech offer full fitting of the VIS internals in-house, and probably part of a ‘+’ map. Maybe worth giving them a bell to see what your options are.