I don't know about that boat. I dig the nacelles, the pylons and the secondary hull for some reason. But that saucer doesn't seem to fit. It could be my eyes or it could just be the angle, but the whole saucer seems lopsided.. Also, I really don't get why they would waste so much possible volume by having a massive gap in the middle of the saucer! I always thought of S31 as being pragmatic, practical and efficient. Valuing the ability to get the job done over coolness, but that boat just screeches "LOOK AT ME I'M SO COOL I'M BIG AND I HAVE A HOLE IN MY SAUCER LOOK AT ME LOOK AT ME AND I'M COOL YEAH".
Maybe it's not a S31 ship after all. Perhaps it's a ship that the feds built as a response to nero, which the section had an influence in, only for Harrison to steal it (as part of an operation for S31/some other agent perhaps?)