Don't go for the FE. Every review show high temps (like thermal throttle high). Blower style cards tend to be noisier, they gather dust easier and are harder to clean.
For the sli i wouldn't bother. You would waste a lot of money in electricity, higher system temps and of course sli comes with its own set of drivers issues.
As mathgeek said, go for an non reference design 1080. If you could sli that in the future it would be a much better scenario, with the low power consumption that 1080 has.