"so I can push the power button while im driving down the road?
what will i gain?
will it mess up my trany?"

Yes, you can push the power button at any time. There will be no ill effects to your tranny. It's a firmware change triggered by pressing the button so it's all electronic.

I'm not sure if it raises the shift points, lowers the shift points or spreads them out. All I know is that it 'feels' like it has more power just because you can downshift easier.