ΔE 32.1, loose: different enough that you should pick on purpose. Exile Blue is noticeably darker, much more muted, cooler than Kakophoni Purple.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 32). Exile Blue is noticeably darker, much more muted, cooler than Kakophoni Purple.
The same difference applies the other way round: Kakophoni Purple is noticeably 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 Kakophoni Purple on the colour wheel See Exile Blue on the colour wheel
All matches: Kakophoni Purple equivalents · Exile Blue equivalents