This is the antenna i got:
If the engenius is RP-SMA i'm pretty sure its going to work.
I'm really not looking to mount the antenna outside. I think its ugly. I wonder how it'd do if i mount both the usb adapter and antenna inside the dashboard.
btw, i just tested this antenna with my dlink pci wireless card and noticed that the signal strength of my connection did not increase much but what it did was pick up like 4 more APs around my area.