The O-3 black looks like it's a bit more head light than the white. But they've got so many of these things out now, it's hard to keep them straight. A head light racquet will feel lighter, even if it's heavier. You will get a bit more racquet head speed from that frame.
I'd say demo both at the same time from Tennis Warehouse, or someone, and pick the one that feels best for you. Both are good frames.
As for getting more power, you can go with lower tension to get that.