Is it possible for a 16 year old to go to a dealership and rent a BMW M6 for a day?
Not to BMW but like exotic dealership or rental place.

No way. At most rental car places, at least in my state, they won't let you rent a car if you're under 25. With the economy the way it is, some have dropped the age down to 21.. but no way will a BMW dealership let a 16-year-old guy (the highest-risk insurance group) rent an expensive car. And if your parents rent it for you, your driving it still won't be covered by insurance, so if they let you drive it and something happens, you're screwed. Yeah, it sucks :( Did you want it for prom or something?