I am using a genuine Intel X520-DA2 in a T730 runinng pfSense and it works absolutely fine with no modification. Before installing it in the T730 I put it in an Ubuntu PC to run an unlocker script so that it will accept any SFP modules (not just Intel whitelisted ones). I'm using a 10G Direct Attach Copper cable from 10Gtek on Amazon to connect it to my 10G main switch and it works great.