How to protect the black plastic piece
 

What is the best way to protect the black plastic piece that spans the length of the windshield, under the windshield wipers? What spray, wax, or polish should I use?

303 aerospace protectant.

Meguiar's Supreme Shine Protectant... no complaints so far

Using this as well.

303 ftw

A friend of mine loves "ultima trim and tire guard" and I have it and it does last a long time. I usually use AutoGlym Bumper Care but if you want something durable, go for that....only downfall is it's expensive.

ultima trim and tire guard is my top choice for trim protectant. I use it all my new car preps. Expensive. but lasts a long time and does not run in the rain. the rain factor is what seals the deal for me. it actually beads water

unless the client is getting opti coat. In those cases, I put opti coat on all the exterior trim including the wiper cowl (thats what that little area is called fyi)

I love 303 aero, but for interior work. looks great but it just doesn't hold up nearly as well as UTTG.

I just started trying 303 on tires, seems to work pretty good.

yes it does work well. the rubber is a bit porous and I think the 303 can soak in a bit.

but the wiper cowl and a lot of other exterior trim is hard plastic. This is where UTTG takes the cake. but in some instances it needs to be lightly buffed on the smooth non textured stuff. a quick pass with a MF towel evens it all out usually