Hi Weeman.
I fitted VX tail lights but it is the same job. I have a URL with step by steop instructions I will try to dig up. The only difficult part is running the reverse light to the tail lights. For some reason the wiring loom (The bit that connects to the bulbs ) on the drivers side tail light fitted with no modification but the left did not. So I had to run a wire from the drivers side to the passengers side through the boot lining.
Cost can vary. E-Bay have lights from approx $160 a pair to $300 a pair. My local wrecker would do lights, looms, globes and the boot Garnsish for $350. You would then need to get the Garnish painted, approximately $100 - $150. Please don't put the Monaro tail lights in and then leave the VT boot garnish in!!!! I have seen this done and it looks terrible.
Where do you live? If ou are local I can come and give you a hand.
Cheers,
Robbie