PC Upgrading Help

[HexagonIi]

Hey guys, so recently, I got my hands on the new GTX 1070 (yay) from MSI, the armor variant. I was wondering whether I am able to add another GTX 1070 (prob the founders as it looks way more badass than the aftermarket ones), considering that I already have a PCIe USB 3.0 card installed on the Motherboard. My motherboard is the Gigabyte Z87X-OC (non-force edition), and was wondering whether I could add another 1070 and run them in SLI, alongside the USB card. I am not really sure whether it is possible, as I am aware of the PCIe lane limit, but would prefer to consult some people before I add another card. Also, would it be possible to run 1070 SLI + USB card + PCIe SSD (considering to upgrade in the future as my crappy HDD is not helping with boot and load times). Or would I need to resort to getting a Z87/Z97 board with a PLX chip? Thanks for the help!

[LogicalDrm]

Why do you need that USB3 card? Board has 6+2 USB ports and 2+4 internals.

[Mi26]

It depends on the Processor u had, some might cause a bottleneck to the GPU in sli