Not sure on the new bhp figure as there was no 4WD rolling road. I've read somewhere that it's in the region of a 15-20bhp increase on other maps.
Certainly feels like an increase, and the power delivery feels much smoother. Definite signficant increase in torque through 1st and 2nd.
Believe it was done via the port on the actual ECU, which required actually opening it up. That's where the issue arose, as it's quite a delicate and tricky procedure. The contact pins became damaged which meant whilst the ECU still operated fine, it couldn't be written to. However, ECU was replaced with no questions and no cost to me, and it now goes like a rocket.
Like I said, big thumbs up for great customer service.