Eyfinity works ok. I have found you need to adjust the fov or the car is only in the center screen. On 2 x hd5970s i've got everything on ultra except for post processing.
I'm still working out which setting I prefer. Also I dont like the View as is because the driver side protection fills too much of the screen,the driver is too low, (I know this is realistic but its just my preference). Ther is a setting for this in the 'camera.xml' files but I can't seem to load them up to alter it.