I got a 2009 2.4L 6 speed with a wild vibration and noise. It kind of kicks in about 30mph or so but you really notice over 40 and it trails off over 65. Even more weird is when I bank to the right it goes away at any speed. Driving straight it is loud, banking left it gets a tad louder. I know the CV axles need replaced but that has been an issue for a very long time. The mid shaft bearing is solid. Wheel bearings are rock solid with no drag or noise.

I really have no idea what it could be. I have driven cars with some seriously nasty CV axles and never had this happen. The axles on the Mazda have been losing grease and the left side pops sometimes when turning. This new vibration/noise gradually started over the past couple months. It is my wife's car and I am nervous about her driving it.

We have had the car since 10k miles, currently 195k. No CV axle work has ever been done and actually no serious work has been done to the car ever.

 

Without driving it myself, your mention of the noise changing when swaying/swerving sounds very much like a wheel bearing.