I am so tempted to think to hell with it, and go for it with my engine N/A to prove a point. From what I understand, the 2.4 manifold and 68mm throttle body works very well if you have head, cams, exhaust manifold etc.
So if the head and cams on this Vectra are standard, then it's no where near what they claim.
What I don't understand is why people with well known cars claim in a feature that they have mega power, when several if not hundreds of owners are not stupid.