May be we should start slappin' one of them "Diffusers" and "Absorbers" in our cars... (or have it build into the interior... like, plastic pieces with ripples, headliner with acoustically transparent materials with sound diffusers (like ribs and fresnels) underneath, etc... I see the glass can be a major issues...
Personally, I hate salesman talk of somtehing like "oh you put this in the car it'll sound incredible because it has XXXXX".. I'd much rather see (even a ill-represented ones) data/chart/graph of lot of before/after and with/withouts...
Well. I'll go home tonight and pull my RTA and ECM8000 out of the rack and get into my car and start measurin'