carnegie- there are a bunch of SQ competition guys "audiophiles" over at DIYMA.com.. they may be able to assist you further if you dont get your answers here.
The #1 enemy of allowing you to imagine you're in a different place than your vehicle is the reflections off so many nearby surfaces. You can do everything practical to control vibrations, resonances, and road noise, but you still have the battle of the reflections. Unequal path lengths to the speakers is also a challenge, and you can't just add delays unless you only care about the driver's seat.
The best thing to do here is re-evaluate your goals. You will never, ever get an SUV to approximate one of the greatest concert halls in the world. It's as flawed as trying to get the vehicle to emulate a great headphone setup. We have DSP available now that can do wonderful things with the frequency response. We have the methods and products to handle the sound deadening. There are many great sounding speakers to choose from. Getting an adequate audio source is trivial. Finding the right people to build and tune(VERY IMPORTANT) the vehicle is not trivial.