I thought the same thing. I was having a difficult time figuring out for whom I wanted to root. I thought the G8 was a little heavier than a Cobra too. I think they're both pretty close to 3,900lbs. I wouldn't think a slightly heavier car would pull that hard away from another car with just a 40whp disadvantage.
I know it's just not about power, but there is also gearing and driver ability. But that seemed like a real ass-kicking for a 40whp difference.