Vektek: "Are you saying it's wrong to say God's grace is powerful?"
No, not if grace is used and understood as an attribute of God. Just like the example..."God is Power".
It doesn't always sound like you are saying "unmerited favor of God" each time. It just sounds like you are blending the two words, Holy Spirit and grace together, but it is not the same thing. Even though in the first scripture you wrote, it could possibly sound right.
But if you replace the word grace and power with "unmerited favor of God"...does it make any sense in the rest of the scriptures?
That is why I have mentioned before that it sounded like you worshiped grace.