Your PSU is not adequite enough to run the card.
**Minimum 680W or greater system power supply (with a minimum 12V current rating of 46A)*
You fall below the wattage requirement and you have multiple 18a 12v rails to.
This should do the job.http://www.newegg.com/Product/Product.aspx?Item=N82E16817256033
I would personally go higher 1-1.2KW just to be safe and have sufficient power for expansion.
As far as problems go, I have read about heat problems mostly, make sure your cooling is in order and be prepared to install high CFM fans to expel heat from the card. There may be other problem related to drivers and blurring image quality that is usually associated with dual chip cards.
You may want measure the space in your case for installing the card too.