I decided I didn't like the look of my 2017 base wrb chrome headlight housings. I decided to paint the inside black. I also installed the morimoto switchback mod. The install was very easy and I think it looks much better.
Do a search on painting 2015 wrx headlights. There are lots of very detailed guides. It only took me 3 hours. Very easy to do. I will say most guides say you have to bake headlights in order to split them. However for 2015+ headlights they used a new adhesive so you do not need to bake them anymore.
I took my lights apart and just used the original goo. It is like strong sticky snot and just clung to one half when pulled apart. Made it easy to just snap back together.