ΔE 37.1, loose: different enough that you should pick on purpose. Imperial Purple is a little darker, much more muted, cooler than Genestealer Purple.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 37). Imperial Purple is a little darker, much more muted, cooler than Genestealer Purple.
The same difference applies the other way round: Genestealer Purple is a little lighter, much more saturated, warmer.
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 Genestealer Purple on the colour wheel See Imperial Purple on the colour wheel
All matches: Genestealer Purple equivalents · Imperial Purple equivalents