ΔE 7.8, close: similar, with a visible difference side by side. Sun Bleach Yellow is a little darker, cooler than Imp Yellow.
Usually, if you are not matching paint already on the model. Close match (ΔE 8). Sun Bleach Yellow is a little darker, cooler than Imp Yellow.
The same difference applies the other way round: Imp Yellow is a little lighter, 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 Imp Yellow on the colour wheel See Sun Bleach Yellow on the colour wheel
All matches: Imp Yellow equivalents · Sun Bleach Yellow equivalents