I've never ran a fuel additive with the VXR, because it's always been run on 99ron Shell V-Power, but I've seen people add further octane boosters to it. Also seen people who are mapped having to use it when there is no super unleaded available, to bring the ron rating back up.
This is what I've added to the engine oil, gear box oil and engine coolant : http://www.team-zx1.com/
It can also be added to the fuel.