Plato, Neo-Platonism and Augustine

I wanted to add a summary to how Plato and specifically Plotinus, a Neo-Platonist may have had some influence on Augustine.

To summarize the relevant points under Plato's philosophy: Basically Plato taught that the real world was the world of ideas, or forms. These forms were perfect universal abstractions from what we come to know as reality in the material world. The relevant piece for Plotinus and Augustine is that the realm of the immaterial, the ideas is the true world that we must strive for in our mind's eye to realize. I believe that at the heart of the forms was the triad, the good, the true and the beautiful. I can't quite remember if Plato gives primacy to the good. Here is where Plotinus picks up.

Plotinus taught that at the highest level of reality there was the One, or the Good. This is God. But God is completely transcendent, and so it is impossible to predicate anything of him. There is no creation, the world around us is far removed from this one and emanates several levels from the one, like light from the sun. Human beings have a higher and lesser part of themselves. The soul is the higher part and the goal is to seek mystical union with the Nous, or Mind which is a secondary emanation from the One.

Some elements of Plotinus that come up in Augustine: Matter is tends toward evil because it is far removed from Nous. Evil itself then becomes privation. Augustine argued elsewhere that evil is the absence of good and has no reality in itself. This is more or less straight Plotinus. Plotinus had strong elements of mystical union with God, though his thought tended toward ecstatic mystical union. Also Plotinus wrote that to achieve this union one must not look outside oneself because God was everywhere present. This is used I believe is closely reflected in Book I of Confessions toward the beginning.

So the question remains does Augustine legitimately adapt or illegitimately adapt elements of neo-platonism into his Christianity? In other words does it destroy of pollute the integrity of his Christian system?