VZ got a 4L65E box which is better than 4L60E which VY may have had (can't remember). Standard box is as Jennie describes but after the Oztrack tune they are as good as any 4spd auto you'll ever drive. Box is fully ECU controlled and a good tune fixes them. Mine was a slug before the tune and exhaust and shifted awfully. I only got mine tuned for E10 or 95 and it picked up about 40kW, went best on E10 or 98 though. If tuned for 98 it'd pick up another 10kW, E85 you'd probably get another 15-20kW again. On E10 it'd do around 14L/100kM around town, highway about 10L/100kM.