Well it's pretty obvious 99% of the systems we install in our cars have the subwoofer in the trunk or rear area of the car... given this fact I can see why bass waves would be coming from the rear -> front and give that punchy bass hit in your back... But has anyone been able to create the illusion the bass is hitting from the front? That's one thing my system is lacking.. The concert sound is there and the stage is phenomenal.. I just miss the kick drum hit in the chest.
Aura bass shakers mounted in the rear of the seat I would image might help if they were reverse phase.. but maybe a seatbelt caddy mount would be better. Haha.