ΔE 24.7, loose: different enough that you should pick on purpose. Spiritstone Red is noticeably darker, more saturated, warmer than Fluorescent Magenta. They are different kinds of paint: AK Interactive Fluorescent Magenta is a fluorescent or effect paint and Citadel Spiritstone Red is a technical paint or medium, 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 25). Spiritstone Red is noticeably darker, more saturated, warmer than Fluorescent Magenta. They are different kinds of paint.
The same difference applies the other way round: Fluorescent Magenta is noticeably lighter, more muted, cooler.
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 Fluorescent Magenta on the colour wheel See Spiritstone Red on the colour wheel
All matches: Fluorescent Magenta equivalents · Spiritstone Red equivalents