I don't think you need to worry about the switch, the 2.5 does the PWR mode automatically. Yes these trucks do shift all goofy BUT regearing solves the problem, if it's that big of a deal just do the job properly and don't waste your time on switches and nonsense. Regearing is not a bandaid fix, it is THE fix. I've owned many different combos of Gen 2 with almost all different gearing options (minus 3.5 DOHC and 4.90) these trucks can pull power and i'm pretty sure the only reason they got 4.27's was for emissions.

Otherwise

If you want to run "Power mode" you need to mash your pedal, if that's not enough get 4.90's.