FOR the VZ Holden Calais, a new, refined V6, a new five-speed automatic transmission and electronic stability control are all grounds for considerable excitement. This is the sort of sophistication that could finally wash away remnants of the cultural cringe that hovers around our homegrown cars. And it does, although in the metal and on the road, the differences are actually quite subtle. The new V6, as we already know, is less spectacularly different than we expected, while the five-speed auto merely brings the Holden into line with everybody else. And the electronic stability control? Well, like airbags and impact-absorbing body design, it’s in the category of being one of those things you hope you’ll never get to experience.