+.45s Red Bull
+1.40s Force India
This is all based on what I have read about the power units so far. Mercedes said they improved their PU in everything (0.6-1s gain maybe), so based on that, I think it's safe to say they will easily beat Red Bull, probably with even bigger margins than I posted. Renault said they improved their engine with a gain of 0.3s per lap, so assuming Red Bull has slightly better aerodynamics than Mercedes, they stand where I predicted them to.
Ferrari is the big unknown here, they have been very silent about their car, haven't talked about their Engine at all, and neither has the Haas (Sauber is using 2016 PU as I recently learned), so there's 2 options, either they made minimal improvements, like 0.15s per lap, or they have made some serious gains, and don't wanna talk about it, like a minimum of 0.5s per lap, possibly even more. I find it hard to believe so, which is why I ranked them third, about 0.65s behind Mercedes, thinking they have improved their Aerodynamics a little bit, but if they have really improved their PU, then they would be 2nd, around 0.35s behind Mercedes.
The rest is probably gonna be 1+ seconds from Mercedes, I think the gap between the mid teams and the top 3 will be even bigger than last year, maybe that excludes the Toro Rosso, Renault, and McLaren if their claims about reaching Mercedes 2016 PU levels are true. Sauber seems like a slow car, having budget problems and an old engine.