I cannot see them supercharging the whole fleet. GTS maybe to distinguish it from the rest of the pack, like it should be.
Not 100% on the years but I'm thinking 98-05 for the LS1 in Commodore models which is 7 years. Definitely around for more than 5... but what about the old 5L, that was around for a long time so it's not like they are going to change it up just for the sake of it.