Painting black trim on the rear bumper
 

You know the one right above the exhaust, I have never been a fan of unpainted trim. I am having a hard time imagining it painted though, thoughts?

It could make the car look a little classier, richer... a little less cheap.
Kind of like a clear-coated piece of carbon trim might look back there... But not so bling. I say try it, it could look really good on white, silver or red!

Have you looked at the garnishes Toyota Japan sells for the front and rear of the 86? Look at Garnish Set B here, and see what you think. (By the way, that says it's Rear Bumper Garnish Type B, it's painted in body color, and it costs ￥43,050).

Are u talking about the rear diffuser??? I think it fits the car... If u have an issue with it... Maybe consider a black car cause the it wont stand out as much... IMO this piece makes me like the rear bumper even more....

This will not look good IMO. It will cause the rear bumper to look much bigger. There's a reason it came black to fool your eye.

The back end of this car is just beautiful, I can't imagine messing with it.

I also suspect it will look like turds. My Civic has a lower bumper area vaugely like the twins. It was the same color as the body, and I ended up painting it bumper black. Looks much better now.

I personally think it would look cheaper painted, but by all means photoshop it and paint away if you like it.

You could paint it but it is almost impossible to paint plastic and have it look really good especially if you do it yourself. Many plastics used in automotive applications will repel spray paint and other types of paint. I have personal experience with spray painting automotive plastics and it can be hard to even get the primer coat on properly. It can be done but expect to screw up at least once and have to strip all of the paint off and restart.

Would black vinyl work?

I would say you will definetly want to have a pro paint it. Would probably cost 2-350 at most body shops if they have some black paint mixed up. Obviously, depends on the shop.

Most of the work will be prep, as is typical. In this case:
Sand sand sand! That textured plastic will have some time in sanding for sure to get it where it is not visible under the paint.
Then primer (automotive primer). Then paint (automotive urethane paint with flex additive), then urethane clearcoat! :)

Spray paint from a can will not have the same results as automotive paint. Now you may have a better idea why paint work is costly. :bonk::bonk: