Make sure you remove it from the car. In some instances "Flat Black" looks great on parts that aren't seen that much. The gloss black can crack or have the shine fade.
First clean it throughly. 5.0 offers a prep cleaner that works great. I used it on the vinyl interior parts as well as the plastic pieces before painting. Make sure you lay down even thin coats. Likely three or four coats will do it.
It will look great and save yourself the $120 price tag for something else.