Adding metallic overcoat to my existing paint

[Elu]

I have been contemplating adding a metallic or pearlescent clear coat to my white paint job to add depth. Although I like the white paint, I thought that adding a metallic clearcoat would really bring out the flared fenders and curves of my '74 911.

Has anyone done anything like this? Is there alot of prep work or can they just sand down the white and apply the metallic?

At this point it's just a question.

[Elu]

Bumping this...

[Bob's Flat-Six]

I'd be careful trying to make an already good looking widebody better looking. I would just give it a good waxing.