2017 Cadillac CT6 Three.0 TT Premium Luxury review: Going somewhere fresh The Three.0 TT is also the very first (claims Cadillac, and you’re free to debunk if you can) turbocharged engine with cylinder deactivation. At light fountain, the Three.0 TT will shut down three cylinders for diminished fuel consumption. Over four hundred fifty five miles of driving, we recorded 21.6…