The "Final Form" or the further evolution? I suppose it would help if we knew how his transformations worked. I know he's a mutant, right?
I'm interested if they're going to show any in between transformations or if they're going straight from 1st to 4th during the movie and THEN his further evolution.
The first three Frieza forms are actually shells he uses to contain his true power (4th/final form). I think he claims his true power is difficult to control so he gives himself handicap forms (armored first appearance = -3 form, first transformation = -2 form, second transformation after Piccolo fight = -1 form). Bit strange but I'm pretty sure that's how it all works. The form in the movie will be a further evolution (which is what Cooler's transformation is, something he says was previously unheard of).