Upgrading some stuff

Hello, I had bought a pre-built computer about 2 years ago and a year ago I bought some new parts. The old one had the GTX 760 and I upgraded to the 970, the CPU was i5-4440 and now I've upgraded it to i7-4790k. The most thing that bothers me is the motherboard, I mean, it feels like it's not as functional enough as it should be, it's the MSI B85M-E45, it feels like it's not future proof, what motherboard would you recommend if I ever wanted to SLI 970's(I've been thinking of doing that) and what PSU is fairly good for a SLI config. I've got the EVGA NEX650G And is it worth upgrading to a DDR4 motherboard? If so, any good ram sticks? Would appreciate if you could drop Amazon links since I'm a refunder myself haha, can get the things for free.

My current setup looks like this:

Motherboard: MSI B85M-E45
CPU: i7-4790k
RAM: 2x4GB RAM STICKS(too lazy to open it up to see what brand it is, but I assume it's not bad)
GPU: GTX 970 4GB
Cooling: Corsair H100i
Case: Corsair 750D(dunno the reason I actually bought it, it's damn huge, it was like 180quid, bought it from Amazon and SE'd it anyways so)