Are you thinking about buying that fixture new? I'm sure you can get a much better deal on a used one here 
If you want to consider SPS you are going to need more light. It is usually suggested that you get the biggest light you can afford from the start so that you don't have to re-purchase one down the line. In this hobby many people end up upgrading their tank size eventually, best to be prepared for that.
A 2 bulb fixture won't give you the bang you really need for SPS and you may well want to have actinics that come on before and after your main bulbs go off (cause it's darned hard not to stare at your tank 24/7)..lol