Philjolet, the only single driver units I am aware of have those paper whizzer cones in them. Typically they are on the low end, price wise and I am sure they aren't intended as anything but a cheap, full range speaker with limited ability. They do make good coaxial speakers but separates are really the only way to go. Getting the tweeter placement higher up in the car and properly positioned is the only way to get anything approaching stereo separation. Anything less is just so much noise coming from your door panels.