The 2016 Cadillac ATS-V is not your grandpa's Caddy. Neither is it the BMW M3 or M4, despite the team responsible for the sedan and coupe duo admitting that the Bavarians were the primary target. V-Series has been Cadillac's sledgehammer retort to German Autobahn-bruisers since 2004, and the ATS-V is the third generation of car to wear the badge. It's …