Pci-e SSD adapter question

Probably you wont' have any speed gain as you use a single x4 pcie slot for 2 m.2 SSDs. To have a faster solution, you would need at least a pcie x8 adapter with two m.2 slots, but the ultimate solution is to have a quad x16 pcie - m.2 adapter, like this one below:
SQUID PCIe Carrier Board for M.2 SSD modules
http://amfeltec.com/products/pci-express-carrier-board-for-m-2-ssd-modules/

The only problem with this is its price. It is around £370 after import tax and VAT.

Hopefully we will see more companies start selling x16 quad m.2 - pcie adapters (most probably Chinese cheap ones first)