Are you sure they said it would increase power? I think that would be the coolant bypass mod since it removes the coolant lines from intake area. But it also results in slower warm up.
The Pathfinder mod is really only needed (and even then probably not) if you are running a lot of boost on a built motor. Otherwise, it doesn't do anything. All it does is unblock a coolant port in the back of the engine so coolant can maybe flow more evenly. It's a bigger deal if you're running a sleeved block since those can have hot spots due to the closing of the deck. But if you have a standard motor, the coolant is flowing just fine. I don't think there are any datalogs that show lower coolant temps or anything like that.
It's also a bear to install with the motor in. Have to remove a lot of stuff and it's tight back there.