I am trying to decide what color stripe to go with or if I should not have a stripe. Any suggestions?

Car is grotto blue with black interior.

I would go with a white stripe. I think a black one would get lost.

white definitely

White would be the norm.

I would maybe try some experimentation with Photoshop or a similar program. Silver might look OK. But easiest to experiment with a picture rather than real paint. Much easier to change. :D