As far as creating an extremely real sound stage, that is the best location believe it or not. It is the best loaction to hav eht RH and LH speaker equa-distant from your ears. The sounds basically will then arrive at your ears at the same time. As far as it appear to be high in the vehicle, that is through the dynamics of sound. Depending on the acoustics of the vehicle it should work just fine. I have always used that location for my front stage when I build audio competition vehicles. Sound is interesting, when low frequencies are emitted from a speaker, they go out and then fall or drop down, highs are the opposite. They go out and then rise, therefore working well in this condition. Good spacial seperation and no timeing delays that would have to be corrected either electronically or with phase invertion.
Basically to me it sounds true and real at that location. I am impressed to see speakers located there in a Z. I have always wondered if it was easy to accomplish.