Historically intakes don't really shine on dynos. Seat of the pants difference...it's there but minor. Certainly far from the best bang-for-the-buck mod at $400.
That said, I do have an intake (AFE) and after the DP and tune went on it really woke up the sound of the intake. It does sound really good but ultimately it's up to you. Would I buy it JUST for sound- absolutely not, there's better ways to invest 4 bananas.