I can't really answer the SLI question, this really depends if companies continue with this whole doubling up nonsense.
I really don't think you need to overclock that, you won't notice any lag whatsoever with those parts.
And as I've said, if you aren't overclocking, you don't need low latency RAM, it's a waste of money. Anyone wanna tell me why he should buy low latency RAM, apart from the fact that "the timings are lower so it must be better logic." I'm just telling you now there will be no difference between 4-4-4-8 and 2-2-2-5 timing RAM at stock speeds.