Whatever suits your taste mate. It's your car after all. Also depends on what size you want..... Some wheels look awesome in 17" but pants in 15" if you get me.
If it was me, I'd be going Comp MO in 16", in silver. With amber indicators and OE rear clusters. But thats me.
Post asking for pics of black S2's on different alloys in the pics+vids forum and see what grabs you!