I have to agree that this implementation of Logic7 is junk. We had Logic7 in the 335ix we sold to get the GLA and it was truly amazing. Spatially it sounded like you were in a nice hall, yet sound stage was front and center. Bass was deep and no distortion.
On the GLA, there is distortion at mid to high levels, bass response is weak, treble is flat and out of the gate, centered fader is rear-centric. So far I pushed the fader one notch forward and that helped a bit. Source-wise, this is another issue I have in that it seems sound settings (at least in my non MM car) are not source-specific. So if you get it just right for a CD or iPhone feed - the radio will sound wrong and vice versa. This smacks of cost cutting on speaker elements. In BMW-land we had Bavsound (google it) - they found speaker drivers that matched impedance to existing system, but were light years better. A great, afternoon project, to swap them in. The other thing the BMW crowd did was figure out that in many cars the bass was not sufficient. However, they found aftermarket subs that dropped right into the same spot that changed the entire system with just a swap of the sub speaker. Come spring I may chase that ghost, but for now too cold to wrench on the car.