I like the changing color idea, good call. But I do like to have the health bar up so the green rage bar looked weird to me. I made a new Rage Bar aura that starts dark red until 59 rage, then from 59 to 119 rage it's bright red (very slight orange) and at 120 it is yellow.
Here is the pastebin: http://pastebin.com/wwRHmh2K
If you'd like to change the colors, you can find the custom code under the "Animations" tab. If you wanted to change the 59-119 rage color to green for example you'd change these lines below
Code:
if player_energy > 59 and player_energy < 120 then
red, green, blue = .9,.2,0
to
Code:
if player_energy > 59 and player_energy < 120 then
red, green, blue = 0,1,0