Mods don't matter for the "power to weight ratio", but any mods done to the car would be altering emissions, which would then make the car defectable, and would require an EPA, which is why your friend in the Silvia got done for mods
Do you know if those are the figures vic roads and the police carry?Can someone with an R32 take a photo of their rego sticker and post up the weight claimed on it?
Thanks