MH bulb question

[freezetyle]

In my tank i currently have a 14k stock sunpod bulb. i like the color of it but after flipping through the tank journal and picture sections i love the color vibrance comes out on the corals with a 20k bulb.

I have a mainly Zoa dominated tank with a few montipora, and acro, and a birdsnest. I guess my main question is would the switch make a big difference on growth of both my zoas and sps?