I agree with Anth0ny in that I think when it comes down to it, Suzie is going with Ken and Crystal, not Matty. It was Ken and Crystal that brought her to the alliance in the first place, and she has to realize that the jury would vote for Matty.
Ken may have to think about blindsiding Matty or even Sugar if possible right now. Bob is gone once it gets to the final 4, though maybe they boot him after a Matty/Sugar blindside to make sure he doesn't get immunity in the final 4.
When it comes down to it, Suzie, Sugar, and Crystal are hated by the jury and are not getting jury votes unless it's the 3 of them in the final 3. I actually think Corrine might get the onion alliance to side with Ken in the jury. If Ken can blindside Matty, there's really no reason why Ken couldn't take Sugar into the final 3, blindsiding either Suzie or Crystal.
If you look at it from Sugar's angle, the best scenario would be to get rid of Bob, blindside Matty in the final 5, and then use the idol in the final 4 to get to the final 3. If Ken realizes this and can convince Sugar, he's golden.