Well done evo. You got the GTX580 in the end. You'll be happy and then in the future, you can just buy another GTX580 to benefit from SLI.
I played the BF3 single player campaign today, got it from torrent sites. Ive only the one GTX 580 1.5gb and Im running at 2560x1440, which is a bit higher than 1080p, and it was very smooth. I didnt have it on ultra though, just the first option was set on ultra, everything else was on high. I didnt select those options, it was the auto settings that chose them. Ive not overclocked anything yet, except for the standard overclocking feature on my p8p67 pro.
My next step is deffo to get another 580, but its not required at the moment. You are going to be so delighted to finally be away from that xbox 360 of yours, when you see friends playing BF3 on it, you will have to hold back the laughs at how poor it is in comparison!
Another good thing I found out today, which is slightly off topic, the communications rose is back in BF3!!! Halllelujah!!