Light questions/upgrade?

Here is the deal, right now I run a 250w metal halide 4' square box, I am just vegging the plants in this until I decide they are ready for the outdoors, last year I had about 30 plants starting in there and they did fairly well until they were 1 1/2' under the 250w MH, then I moved them out and started more, but the problem was they did'nt grow fast enough for me to get another batch out,

I am thinking about getting two 200w CFL's (the twisty ones) to go on both sides of the box (the MH is in the middle)

Is this going to help the plants to grow faster?

Anyone ever mix MH and CFL in the same room?

Yes, I have. That works well. Mixing light is always good. More blue in veg and more orange (red) in flower but the mix is good.