on a 3dr i assume as you can't on a 5dr...(rear end is different)
Front bar + all the bits you need (grille, fog light inserts etc) works out to like $2k....the skirts can be picked up for just over $500... and the rear bar would prob be about $1k. then you have to pay for it all to be fitted and painted
not cheap...
Also...if you do the VXR rear bar, your exhaust will have to be modified as it needs a centre exit, prob easier to just go the SRi-T rear bar.
And you could try wreckers etc...or SSV...but being in perth, your cheapest option is going to work out to be Holden...what a scary thought that is...