I have the specs of as tested (not holden specs) v6 commodores from vn through to vt, and the fastest v6 commodore from 0-100 is the seriesI VN executive. If I remember correctly the VN exec is also the fastest over the quarter mile.
I will have a hunt around at home and see if i can find it.
Aside from the specs though, I am of the opinion that the seriesI definatly had alot of low down punch, but really lacked any top end whatsoever.
The seriesII in my wagon seemed to be a step above the seriesI, in terms of mid range grunt, and the missus' VX just seems to want to rev forever.
In a head to head dash nowdays I think the Ecotec would beat the seriesI 9 times out of 10 due to the seriesI wheelspinning and the eco just taking off.........
Thats my 2 cents.