Pink Horror vs Sunset Purple

How close are they?

ΔE 24.2, loose: different enough that you should pick on purpose. Sunset Purple is noticeably darker, more muted, cooler than Pink Horror.

Can I use Sunset Purple instead of Pink Horror?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 24). Sunset Purple is noticeably darker, more muted, cooler than Pink Horror.

Can I use Pink Horror instead of Sunset Purple?

The same difference applies the other way round: Pink Horror is noticeably lighter, 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.