Now, this new rear-wheel-drive flagship will initially debut as a four-door coupe, but a coupe and convertible are expected to follow sometime in 2016. The car will ride on a new RWD chassis developed by Holden, but its engine lineup hasn't been decided yet. Rumor has it that anything from a turbocharged four-cylinder, through a twin-turbo V6, to an updated version of GM's 5.3-liter V8 could be utilized. Even a production version of the Elmiraj concept's twin-turbo V8 is possible. Whichever engine wins out, it'll be paired to either a nine- or ten-speed transmission. GM also trademarked "LTS" earlier this year, so expect for the Elmiraj name to be dropped.