Wax over Stripes or not ??

Depends on the wax. You can apply Turtle Wax "Ice" over anything. It actually makes flat black plastic & rubber even "blacker".

Ehhhh, Ice is alright but there are much much better options out there. I have used it on my matte black stripes before and it made them shiny. Meguiar's Synthetic X-Press Spray Wax (D156 for short) is a better product and costs WAY less. It also streaks much less than Ice. Turtle Wax products in general are just not very good. I hang out on detailing forums and the first thing we tell people is to ditch the Armor All and Turtle Wax and get some decent products to start with.

Spray waxes also provide no long term protection and they're better suited for wiping off dust and bird poop than to actually be used as a wax. Washing your car or driving in the rain can wash a spray wax right off.