ΔE 14.3, fair: the same colour family, but not a straight swap. Alien Purple is noticeably lighter, more saturated than Purple.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Alien Purple is noticeably lighter, more saturated than Purple.
The same difference applies the other way round: Purple is noticeably darker, 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 Purple on the colour wheel See Alien Purple on the colour wheel
All matches: Purple equivalents · Alien Purple equivalents