Neither of those cards will max out BF3. A single 580 won't max out BF3 either, though. Personally, I think the 580 is still a great card. $

erformance be damned, it still has better performance than any single Nvidia GPU. If you can afford it, by all means. No one can guarantee you max performance on new titles for 2 years though, don't ask for that kind of reassurance.
Per your edit question, yeah, that's the kind of cooler. There are a host of aftermarket coolers like Zalman VF or Arctic Cooling stuff that does an even better job (the prior of the two can be found on Zotac cards), but they generally require reference cards to be installed properly. MSI Twin Frozr and ASUS DCII are the best of the bunch otherwise.