ΔE 11.2, fair: the same colour family, but not a straight swap. Magnus the Red is a little darker, warmer than Terrestrial Titan.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Magnus the Red is a little darker, warmer than Terrestrial Titan.
The same difference applies the other way round: Terrestrial Titan is a little lighter, 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 Terrestrial Titan on the colour wheel See Magnus the Red on the colour wheel
All matches: Terrestrial Titan equivalents · Magnus the Red equivalents