it depends me and mate tested to see if my ute cud beat his brand new ve sv6, i got like a car length and kept pulling
depends what condition there in, power to weight ratio ect
just thought ide might add something, im driving an vz sv6 5 speed auto, me mate has a vx supercharged calais, weve had a few runs and on a standing start he will pull up quiker, wud be the abundance of low end torque but on a rolling start at around 35 kays we are pretty much dead on, also wiht vz have a better auto, in the higher models anyways, u gain an extra cog and its a little smarter when it down shifts, holds gears and so on. i do like the 3.8 but i think the alloytec is much more flexible, this is in my own opinion and also the better fuel economy isnt bad, i manage about 10 - 11 litrles per 100 k around town if u drive like a granny and 6.8 on the open roads.