Just was looking around and I found some reference for a feat: Improved favorite enemy. Its a ranger attack but I can't find any reference for what this feats bonuses are. Has any one else head of this feat?

You need several levels of ranger, I believe, and it simply provides a bonus to the existing bonuses against said favoured enemy. Like +3 spot, or some such. I haven't actually taken it myself, but I'm sure you can experiment with a character builder or some such.