Warp Lightning vs Acid Green

How close are they?

ΔE 44.1, loose: different enough that you should pick on purpose. Acid Green is noticeably darker, much more muted than Warp Lightning.

Can I use Acid Green instead of Warp Lightning?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 44). Acid Green is noticeably darker, much more muted than Warp Lightning.

Can I use Warp Lightning instead of Acid Green?

The same difference applies the other way round: Warp Lightning is noticeably lighter, much more saturated.

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.