I also assume that a flat-bottom, 210hp F3 Dallara would not be competitive with a current SCCA Atlantic, kind of like the Pro Mazdas or the Fran Am cars. They are allowed to run, but they will not beat a top-flight Ralt or Swift. Most Ralt or Swift owners would probably have no problem with a 210hp F3, but if the car were allowed to have 250 hp there may be a quite different reaction.
It seems to me that the engine issue is the key to this discussion, whether we are talking about the Swift 016a, Dallara F3, or any other car. These cars will require approval of alternative engine packages if they are to compete in the FA class, and as we have seen in FC this will be very difficult to do without harming the current Toyota/Cosworth competitors.