[Phanx]

Originally Posted by Vlad Hmm, I hooked the SetStatusBarColor but the C-code doesn't seem to fire in a way that the hook also fires, meaning the color remains purple.

Try hooking it this way:

hooksecurefunc(healthBar:GetStatusBarTexture(), "SetVertexColor", function(texture, r, g, b, a)
    print("statusbar texture vertex color changed to", r, g, b, a)
end)

I'm pretty sure healthBar:SetStatusBarColor() is really just a wrapper for healthBar:GetStatusBarTexture():SetVertexColor() in which case it would make sense for the internal API to just call that directly.