ΔE 24.8, loose: different enough that you should pick on purpose. Sulfur Yellow is noticeably lighter, more saturated, cooler than Imperial Fist.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 25). Sulfur Yellow is noticeably lighter, more saturated, cooler than Imperial Fist.
The same difference applies the other way round: Imperial Fist is noticeably darker, 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 Imperial Fist on the colour wheel See Sulfur Yellow on the colour wheel
All matches: Imperial Fist equivalents · Sulfur Yellow equivalents