The only number that's been floating around (which may not even be accurate) is that they are producing FRS at a 3:1 or even greater ratio than the BRZ.
As far as who is 'winning' is concerned, maybe you can say Scion is winning from the visibility perspective due to the sheer outnumbering of FRS vs BRZ on the road.
As far as winning in terms of profit - we would need some answers about the money split.
Does Subaru earn money for every FRS that is sold granted that their engine is in it? What % profit? Does it work vice versa for Toyota / Scion for every BRZ sold? Again what % profit that way?
I think it would be safe to say at this point that they are looking at profits.. for both companies, not only in monetary terms. Scion brand has taken a leap and Subaru is now in the RWD sports car scene.
But in the end... does it really matter for us as the consumer? An 86 is an 86 in my eyes and what I value as 'winning' is that each of us 86 owners have a long satisfying relationship with our cars.