Do not take my one opinion alone please. Look into it. If you do want a top to bottom SPS reef then you will most likely need new lights. If you are willing to limit your SPS to the brightest couple of spots under the MH and have LPS and Soft corals populate the rest that would most likely work also. Like I said before I have a SPS tank lit by only VHO and it is doing great. It is 58 gallons with 385 watt of VHO.
If you do decide to get new lights give the board sponsers a look. Mention TRT if you can. it is always good to be nice to those who work for free.
Scott Morrels (sp?) 120 started with NO's and SPS's. He did okay. He later up-graded to VHO's and is satisfied and has better growth (no big suprise there). Point is, lighting is one of those things thats just has so many variables, its hard to make a call on.
Personally, I would recommend MH minimum. I have a 125 thats 72x18x23(ht.). I am using 3 x 250 6500k in conjuction with VHO's and doing rather well. Gotta about 8.5 watts per a gallon. Just food for thought, take what you want and toss the rest of my reply....