Z170 Chipset x i7 6700K x m.2 SSDs

Hello!

I have a couple questions...

The Z170 chipset supports up to 20 PCIe lanes but i7 6700K processor only has 16, what happens with the other 4? They are disabled or some way can be used?

Counting only with the 16 PCIe lanes from i7 6700K, if I use two m.2 SSDs 4x like Samsung 950 PRO or Intel 750 series in RAID 0, they will occupy 8 PCIe lanes, remain only more 8 PCIe lanes for GPU wich is 16X, I may have some performance loss?

And to achieve the Ultimate Game Rig (8 lanes for SSDs + 32 lanes for SLI or CrossFire) the only way is using a X99 plataform?

Grateful for the help!