From publisher blurb:
Have you ever wondered why, when the pre-epic class levels allow you to have as many as 23 skill ranks in a given skill that synergy stops at 5 ranks? Yeah, us too.
Superior Synergy introduces new skill synergy levels at three new benchmarks: 10, 15 and 20. Not all benefits are merely increases in a simply synergy bonus, either. Some benefits include reduced times needed to perform tasks associated or altered DC modifiers with the synergy skill.
It doesn't end there, either. Superior Synergy also introduces feat synergy. Much like skill synergy, feat synergy allows two or more feats to work together for additional benefits they couldn't achieve on their own without having to take additional feats.