When people say they should have run a different car than what they did are forgetting that these people have the money to develop a suspension that will take the chassis to the maximum of it's abilities and about the only thing thats "vectra" on the car is the badge...

Chances are that the Vectra has a stiffer chassis than an Astra. Making suspension movements much more precise, giving the team the ability to get every tenth they can out of the car, not to mention giving a car thats much easier and predictable to drive, then on standing starts a RWD will out accelerate a FWD in almost every circumstance off the line.