I cant tell you about the OD yet as I just rec. mine.
Set screws on my aggressor.
I was told you could and thought about doing it to mine. I figured time I bought the insert, paid a machine shop to tap it I was looking around $175 or so. I just waited and found a used FTN diverter, figured I would take the money I was going to spend on the upgrade and put it towards the ftn version. I was also looking at a lower profile on the reverse nozzel. So if the FTN version works out I will put my old diverter up for sale and recoup my money...hopefully I will break even.
I have also heard that the older style diverters didnt have enough meat inside to tap out for the inserts. I can not say either way.