In the 70's GD tried to put twin tails on the F-16, but the combination of LERX+twin tails prooved to be unpredictable, so they choose the single one.If those guys achieved to make this thing work nicely (which i doubt) they deserve some credits.
I can't think what serious and practically applied performane enhancement they will achieve. The plane won't be any faster accelerating or any harder turning. Maybe a little better high alpha authority, which is good, but since drag will also rise, they need more powerful engines (then more fuel then heavier structure and so on) to have some real operational benefits.
It would be far better if they tried to put a new bigger and lighter wing (made from composite materials) like what GD did on the F16/F-2. This would increase operational range, payload/range ability and maneuvering performance substantially.
Just my 2 cent (like a distant but really very good friend of mine
used to say in such ocassions)