The Valve Spring, that's so you can tune to a different weight, you don't need it for a LT conversion.
What you may want to do (which I don't think the kit provides other than a how to) add a bleed hole in the valve body and bore our the valve plate 9or use a 94+ plate and modify that) and alter the preload stack (they're 0.5 and 1mm Alu spacers).
These are all tuning options at the time and a modification when you go long travel DH and heavier rider setup.
Oddly it's not a tuning often done as it means getting a dremel/drill out. Most just ride as is.