what color stripes to use

Since you're talking about just a thin pinstripe, I'd go with a lighter shade of green as an accent. I don't think a black pinstripe will do much since the green body color is fairly dark. The only other color that, IMO, may work would be a silver to play off of aluminum/chrome wheels.
Just my opinion, but I think a pinstripe has to both accent and compliment existing colors. I don't think either red, gold, or orange stripes would do anything to compliment your existing color combo.