I've already started writing a tracking system for this ... or, let's say I have code that does fairly naive detection and amount tracking work. More or less the only way you can do it is to watch for the buff's application, query the aura on the unit to find out the value and then wait for it to either be refreshed (amount augmented) or fall off. When it falls off, it gets trickier. I go into greater detail in this post:
http://www.theincbear.com/forums/vie...p=15057#p15057
When you want to track the effect on a unit that isn't your target, you end up having to get into guid:unit maps to be able to properly track it.