Facelift (04-09) rear lights can be fit into an pre-facelift S2000 (99-03) when you modify the metal rear plate. You need a Dremel/saw and drill.
Its the best to use the facelift rear light gaskets as a template, to see were you need to cut into the metal. These can be bought in our S2000 webshop.
You also need the harness plugs and some harness wires to make these lights work.