After warm up and driving around at speeds 35-55 the car seems to develop a low frequency come and go vibration (gets intense the calms away then gets intense and calms away) accompanied by faint slow wrapping noise. It sounds/feels like a loose or half busted motor mount, gonna check her out tomorrow but just looking for potential ideas. I seem to notice it more cruising in 6th. 5th it seems to dissipate but i can still notice it, 4th or 3rd the engine noise takes over. Coasting it still seems to be there but not as intense. I also noticed it on the highway when I drove the car home after a prolonged driving period. Other then that the car feels great cruising or in boost.

Any input is appreciated as I'm still new to this car.

EDIT: 2006 9MR 14k