depending on state you are in, if a vehicle is under 15 years (you skyline boys will be fine!) if written off, it goes on the WOVR and unable to be rego'd again.
if you manage to buy it back, some insurers wont insurer it again as they'll say it has pre existing damage
anyhoo, as someone said - weigh up the costs. get a quote yolurself, speak to insurer and speak to them about next renewal and see what may happen