The biggest thing holding me back is that its a laptop, and has the problem of thermal throttling. The CPU is an i7-4870HQ and clocks at about 3.6 Ghz, I think the CPU is the bigger thing holding back performance. 2 970's is more than enough, especially if they have more than 3GB VRAM. I agree with the comment about Direct X 12 and Pascal. If there was an update for the game that allowed DX12, the VRAM would double in SLI and give you 6GB if you had 3 per card, or 8 if you had 4 per card. DX12 is the cheapest way for us all to get some extra frames. And when pascal comes out... chips designed specifically for 4K gamers in mind.
Desktop 970s in SLI are amazing if they can pull off those fps numbers at 4K, I didnt read that you were playing at 4K resolutions. That's incredible.
Well not quite 4k I dont have as many issues with running out of VRAM as 4k does