I have an Intel AC adapter and a Gigabyte one.. both were $30 ish and provide 867 Mbps on AC wireless.. I'd recommend either of these PCI add in adapters!
A pci-e M.2 SSD is capable of much higher..like 5x higer speed (2200/900).. provided it isnt a Sata3 interface.. in which case you might as well stay on a typical 2.5" drive (550/500)