Word of warning. I clayed my Black Insignia and made a mess of the paint finish. I had to take it to be machine polished to get the marks out that I had made with the clay.

I have used clay in the past on my silver Vec and the wife's cream Mini with no problems. But as my bodyshop manager says you have to be very careful with black.

I will never use it again.

Go for a good polish Eg Autoglym super resin polish, and then wax on top of that. I use Meguires 16 wax.

To maintain I use a detail spray like Meguires detail spray.