Couple opinions (mine):
The Cobalt or Volks is likely to battle for the win again. They both will be faster than they were before and got allowances last year to this year. Pretty good evidence at the sprints to support that notion as well and the Volks was unchallenged and hotter weather, not a tested race like the runoffs will be.
But the 350z is going to be a weapon at the runoffs. All of them will be at the front and lots of them running "faster than T2 times last year" at a lot of tracks they have gone to and raced in T3 (not surprising).
Me thinks gonna have to be in the high 31's/32's minimum to win in T3 this year. That won't be too hard for the cars mentioned here and the 350 has already shown it can go in the 32's.
T1: Gotta beat Buttermore in his Vette. Don't think that will be easy for anyone and a likely Buttermore/AJ rematch is possible. The other Vette (Onks) and the fast Mustangs (AJ if in one) and Winkler are bad fast.
T4: Mustangs and Honda's will be hard to beat. For anyone paying attention, the newer Civic has quietly gotten a couple of allowances so I think it will be hard to beat.
Don't forget either about the provisional entries for past champions. Take someone like the Heinrocket in a Vette in T1 and I assume he is a heavy favorite. The same could be said for a lot of I think. Pobst in a Mustang in T2 for instance
I don't think any of the T classes are going to well attended at the runoffs unless there are a lot of provisional past winners that show up. The rules seemed to have pinched a lot of cars into an noncompetitive state for this year anyhow - again if you are paying attention