ΔE 15.5, loose: different enough that you should pick on purpose. Permanent Violet Dark is much more saturated than Druchii Violet. They are different kinds of paint: Citadel Druchii Violet is a wash/shade and Golden Permanent Violet Dark is an ink, glaze or transparent paint, so they won’t behave the same on the model even where the colour is close.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Permanent Violet Dark is much more saturated than Druchii Violet. They are different kinds of paint.
The same difference applies the other way round: Druchii Violet is much more muted.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Druchii Violet on the colour wheel See Permanent Violet Dark on the colour wheel
All matches: Druchii Violet equivalents · Permanent Violet Dark equivalents