ED refers to Enhancement Diversification, which is a limitation on the maximum amount of effect an enhancement can improve a power. This is meant to discourage slotting a power for something like six damage enhancements and instead meant to encourage "diversifying" what enhancements you slot into a power, if at all. As a general rule of thumb anything after the third enhancement is getting drastically reduced in effectiveness by ED, and its' generally a good idea to begin slotting something else though this is not so much a rule as general advice; There are certain instances where you might continue slotting a power for the same enhancement despite the diminishing returns of ED.
The different colors are meant to indicate how close you are getting to ED's diminishing returns. Yellow/Red indicates that you are being effected by ED, and the number after "PreED:" determines what your value was without ED so you can gauge by how much you are being effected, and if you want to continue slotting anyway. Of the two a RED colour indicates that you are being effected by ED more severely.
So by your own example, the damage your power is doing is being enhanced by a value of 101.86%; without ED it will be reaching a value of 145.75%, and it is red because you are being HEAVILY effected by ED.
Couple of questions pop to mind when working with Mids that I need some clarification on: This pertains to the info box under the "Enhance Tab"
1. Some of the info displayed is in white, some in yellow, some in green, and some in red. Can someone please explain what they all mean? They all have to do with ED applied.
2. What does "ED" mean? I see the "This effect has not been affected by ED". These totals are all in white.
3. An example of one in red - Damage 101.86% (Pre-Ed 145.75%) This is in red.
I've looked in the read me, but no clear explanation exists, unless I didnt look far enough into it.