You would think that by now some of the silver crown and sprint car drivers would be hanging out of their cars also since it makes you so much faster, to heck with adjusting things JUST HANG OUT!
QMs are one of the very few motorsports where the driver can be 50% or more of the combined weight of the vehicle/driver. The problem I have with "leaning" is the driver being held stationary from the waist down. Just beggin' for a spine injury. You want to see some serious "leaning" watch some motorcross and Karts.