I recently purchased blackfire, but I haven't used it yet ...
I have had great success with EZ-Creme/Jet Seal x2/Pete's 53 combo on metallic paints.
If you are on a limited budget, collinite 845 works awesome on metallic paints and gives incredible protection.
metallic gold is somewhat difficult to make it stand out, so proper polishing is key.
Good luck,
G