As previously stated, painting plastic in a way that will look good and last does require some special practice and procedures. Very do-able for a DIY guy so long as you know what is required.
A couple of other thoughts. If you don't already have mud flaps, you may want to consider some. Without them, I think the paint on the rocker panels will chip pretty easily. I bet Dodge also thought of this and that may be one of the many reasons the rocker panels are all dyed black and not painted. They knew that this area would be prone to road dust/dirt and scratching/chipping. The same with the front spoiler. Take a close look at it. It would bet there are many small nicks/chips that don't look all that bad because the plastic is dyed, not painted.
I think at first, the painted plastic will look great, you'll love it. But unless it is protected, it will look lousy fairly quickly with all the nicks and chips.
Something to consider to preserve the paint may be to add some clear bra material to these components after painting. You will likely have to get some custom cut pieces, but this material will go a long way to reducing the inevitable damage.
You may already be aware, there are some clear bra materials now that have a certain amount of "healing" capability. That is to say that they can sort of self repair/recover from many small nicks and scratches. Might want to look into this option!
Either way, good luck and be sure to post some pics!!