Borg warner s400?

Looking for all you turbo techs. I hv a Detroit 12.7l pre emissions non cylinder oiler motor and it's time for a new turbo. Had a private stage 1 but rebe127 and others said it's basically a 171702. I run mainly small hyway but the future looks as if I'll be doing alot of long big road runs.
I was told the air works s400-75 is what I really want and need. New version of 171702. But seems there are alot of different varieties, 360 bearing?, different inlet and outlet housing, can someone plz school me on what I'm really needing and wanting? Hvnt been able to get a hold of a borg warner rep, but I plan on keep blowing their fone up lol. Thanks for any insight