Meh I'll just go straight to manufacturer if they give me shit. But my local MSY are pretty friendly guys.
Good rule of thumb I read on toms-hardware the other day, was to buy the best single card you can afford / justify, then in 6-12 months SLI it with another when prices for that card have come down even more. For me this was 770, because it's a few months old now, so still a great performer, but with superseded pricing cause of the 780/Titan/690.