The CT6 sedan has already wrapped production and the CT6-V goes away in early 2020 — General Motors’ premium division is in major-overhaul mode. Three of its sedans — the CTS, XTS and CT6 — have already retired, while the new midsize CT5 and compact CT4 sedans are taking their place. Barring a change of heart from the Cadillac brass, the CT6 will exit with a bang and its head held high in the form of a performance CT6-V model. It’s equipped with a handbuilt twin-turbocharged V-8, called the Blackwing, that pounds out 550 horsepower and 640 pound-feet of torque. A 10-speed automatic transmission sends the torque to all four wheels. Along with the go-fast equipment, the CT6-V is loaded with a plethora of related hardware, including magnetic-ride suspension, rearwheel steering and Tour, Sport and Track settings that vary the transmission, suspension and steering functions according to driver preferences.