Answer:
I am perfect with a head perfect without a head; Perfect with a tail perfect without a tail; Perfect with either neither or both.
I am a shimmering field that reaches far. Yet I have no tracks and am crossed without paths.
I will go within you and destroy you. Only because you wanted me too
I get paid to shoot people then blow them up.
I am the only thing that place today before yesterday. (one word)
Though not a plant, has leaves. Though not a beast, has spine. Though many wouldn't need this thing, It's more valuable than wine.