Help me make up my mind.

[Gools]

I'm upgrading my lighting, or at least starting to. I currently have 175w Halides but want to go up. I can decide between going to a 250w or a 400w. Right now heat isn't a issue. My tank stays at 74-76, and I have 2 fans with room to add 2 more, so heat isn't too much of a concern. I have about 20 sps, and I want to keep mostly acros. The reason I want to go up is : 1) to get better colour from my corals. 2) because all my stoneys are cramed up at the top of the tank to try to get all the light. Any other suggestions would be great. Thanks