Your unit is SLI certed.
If you need to have the PSU's cabling changed I am sure PCP&C will do it for you. Only do this if adapters are needed for hook up and you don't want to use them. There has been some issues with the 8 pin plugs used for these high end cards. I could not find the thread about it over at jonnyguru.com but you might want to look over there if no one here offers links to pics.