ΔE 15.4, loose: different enough that you should pick on purpose. Faded Red is a little lighter, much more saturated, cooler than Rust in Peace.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Faded Red is a little lighter, much more saturated, cooler than Rust in Peace.
The same difference applies the other way round: Rust in Peace is a little darker, much more muted, 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.
See Rust in Peace on the colour wheel See Faded Red on the colour wheel
All matches: Rust in Peace equivalents · Faded Red equivalents