Most Z97 boards use additional chipset lanes for M.2, not ones from your CPU.
And on Z97 most m.2 slots only have 2 lanes, not 4.
This means that even if there were an m.2->SFF 8643 card available for Z97 right now it'd still only use 2x pcie 2.0 lanes that have more latency added because of it using chipset lanes and not CPU lanes, and as a result the SSD would not run as well as it has the potential to.
The product page says 4 lanes because the only M.2->SFF 8643 cards available are made for X99, and X99 has 4 CPU pcie lanes for the m.2 slot.
The GPU usually uses the CPU pcie lanes, so it would have no effect.
And even if the GPU had a few less lanes it wouldn't matter since no single consumer GPU currently available uses anywhere near the full bandwidth of PCIE 3.0 x16.
Even if you were to run the GPU at PCIE 3.0 X4 you'd see very little if any degradation in performance in most scenarios.
Just trust me on this, buy the PCIE add-in version instead of the clumsy m.2-> SFF 8643 version.