You just need to cut the radiator support a little, just to round it like the VR/S radiator support, where as the VN one is squared at the edges.
You need to swap the bonnet hinges over too as the VR/S ones differ to the VN/VP ones.
You have to fit gas struts to the engine bay too if your car didnt have them because VR/S bonnets don't have the hole for the VN/P metal rod setup.
Also the pipe for the windscreen washer jets runs out the drivers side of the firewall on a VN/P but on the passenger side for a VR/S so you'll need to lengthen the hose and run it down the opposite side under the firewall cover.
And you need to drill a few holes to fit the headlights as the VR/S headlights mount differently to the VN/P ones.
Oh and you need to cut the plastic shroud bit near the radiator in order to be able to fit the VR/S reo bar.
Pics and instructions are in my ride thread. There are links to the relevant pages on the initial post.