Space Magenta vs Chaotic Red

How close are they?

ΔE 9.7, close: similar, with a visible difference side by side. Chaotic Red is more muted, warmer than Space Magenta.

Can I use Chaotic Red instead of Space Magenta?

Usually, if you are not matching paint already on the model. Close match (ΔE 10). Chaotic Red is more muted, warmer than Space Magenta.

Can I use Space Magenta instead of Chaotic Red?

The same difference applies the other way round: Space Magenta is more saturated, 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.