I think the best use I've seen so far is the Wish method. By RAW, I don't know if +15 is possible due to the way Wish is worded, but +3 for a single Wish, or +7 for 5 would certainly be possible.
The great thing about this feat is that it's a general feat, rather than a metamagic one. This means it stacks with metamagic. An Empowered Cat's Grace with this feat would grant +9 to Dexterity.