I’ll gladly accept your three generations of Viper if you’ll accept my ten generations of Mustang (1964-66, 1967-68, 1969-70, 1971-73, 1974-78, 1979-93, 1994-97, 1998-2004, 2005-2014, 2015-now). My criterion for defining a generation is if the doors will interchange, though I know the first two gens will.