Silhouettes would have to put up a show stopping number with no gimmicks and everything perfect to win I think. Same with Poplyfe and Landau because we're seeing the same things in all three of them.
That said, iLuminate has to have the toughest job here to win this - they will have to top their performances from the previous two weeks.
BTW, I wanted to say something having read a lot about the actual finals acts - a lot seem to have taken a hit by the Russian Bar and didn't do what got them into the finals. They took too big of risks and failed.