I'm sure the car should fit right into the rules of (unlimited class) RTA, in fact the biggest limiting factor that that car has in its Grand Am GT class rules status is its limited (NA) power output. Now with the RTA rules in place for them they will be able to add a lot more power in the Z with some sort of forced induction.
Now, just think if they are saying that they are running just as fast of times as the fastest Unl cars now "as is" with no forced induction, etc.... than holly $hit are they going to be fast when they through more power at that car.