i think its a bit stiff. I would go about 150w.
the alternative is to pull the light away from the tank.
250w would really heat things up. and you can burn corals under too intense a light. although the latter is much harder to do than the first.
no and what are the tank dimensions? I have 150wx2 because its a 3ft tank and relatively shallow (16") but if its a cube or 30g tall a single 250w would offer more intensity and less heat then what I have. My tank runs 78-81 deg and I wish I had of went 250wx2. 150w is just so so for SPS regardless of tank dimensions. I ran 96wx2 pc forever and a single 250w halide is only 58w more watts of heat. If you have heat issues its poor venting/circulation. SPS will grow and look better under 250w, I can almost garauntee it all things being equal as I have done everything possible short of ugly high par low kelvin bulbs using 150w and had MUCH better results with SE 175w in an otherwise dirtier, inferior set up and even then I wished I had of gotten 250w. colors are fine, growth is nowhere near as good as 175w and 250w halides.