Depends how nice you want it to look.

If just brushing it on, those little flat short bristle brushes give a much smoother finish than a conventional brush. Just try on a test piece first as there are loads of loose bristles in them. When clean it's quite easy to get a nice smooth finish
Means touch ups are simple too with brush paint, as it is going to get scratched in some places.

I just used Fortress satin black paint from B&Q ( doesnt require special thinners like shitty hammerite )