I did my lower dash trim panel just today. Well, it's the panel that was in my car but is not correct as per build sheet so I may screw it up.
Just like burdar I cleaned it with water and simple green and a towel (no scuff pad), then used SEM Plastic & Leather Prep 2-3 times and just now one layer of SEM Landau Black. See the pic, the lower part is not even 1 hour after painting. It actually looks glossier on the photo because this is indoor lighting. I'm surprised by how "original" it looks, the color is just how it's supposed to be.
I used a scuff pad and simple green on the other trim part and that part now is veeeery faded so once you scuff them you definitely need to paint them.
Click to enlarge