Thanks for the suggestions, guys. I also reviewed some other forums and found that a group 47 would also fit in my 2016 GT. Since I have a friend who is a regional manager at O'Reilly and he has a 2016 GT350, I checked with him before deciding what to get. We both agreed we wanted an AGM rather than a flooded battery for a number of reasons including that we autocross and battery is subjected to a bit of lateral G-force. He is looking at a group 25, but wasn't sure it would fit since it's about 3/4" taller. The group 47 isn't quite as tall, but still taller than a 96R. One of the other forums had a picture posted of his XS 4700 fitting in the battery compartment and O'Reilly has an AGM in that size. I let them install it and it fits well enough for the battery cover to match up. The cables sit a little higher than the lower gasket edge of the compartment, but it doesn't seal anyway, so I don't see that as a problem.
2016 GT Premium with Performance Package, Guard Metallic