There are several good systems out there, both base/clear and single stage. The latest one that I used is Eastwoods "Dead rat flat black" which is just that.... very low gloss, very black. I shot the rolling thunder Ranger project with it on the show. I've also used Eastwoods Rat rod flat clear on the JADED Mustang underhood and for accents/chassis paint,and was very happy with the clear and how its easy to spray evenly.. SUMMIT's single stage is good, but I fond the PPG 2060 Flexed N flat a little unpredictable.... had a hard time with "striping" in the clear, but for small parts is good. ( Finch has used it with much sucess on his silver Camaro though... may be pilot-error on my part.
I'd stay with a single stage for simplicity, and gently nudge toward eastwood, just for the sake of value combined with a great product... = not expensive.
JMHO
KT.