i seen people who used the dyson hoover expandable piping
on the side of the air box closest to the wing you will see an aparture [extension of the inner wing]
now that is a good place for cold air intake and i seen ppl drill holes in their airbox next to this
tumble drier ducting
you see on the calibra you got a flap on the bottom of the bumper, now inside that area when u open the flap there is a pipe that runs up the wing connecting to the underneath of the airbox
i wonder if we could do something similiar to the vectra, cold air feed going from bumper up to the air box feed