I have to add this......the positioning of the drivers is just as important as the positioning of the port, considering the port will likely have more lowend extension for the total reponse and the driver, being exposed to the environment, will make up the high end extension from front wave propagation. That being said, without determining the actual gain of that vehicle, one cannot determine the optimum positioning when both driver and port contribute to the response. Now, also it has to be pointed out that low frequency resonance will have less directive sound within a vehicle, especially if the port allows for extended time interval of the operating frequencies. In other words, though I would have to see the interior of the enclosure to determine this, the resonances that exist there will likely cause an omnidirectional sound near tuning. And though cabin gain will always control the response outside the enclosure, with these existing resonances along with the drivers being installed across the enclosure to the passenger side, I would not believe port position will have as much issue as you may believe i n this design. Now, if the box does not exhibit resonances beyond 3rd harmonics or so with sufficient output, and the drivers were located in a different position thaton the same plane as the port along with having less drivers used, then placement would be more of a concern. But without knowing the exact cabin gain, and combined response from both driver and port positions, you cannot determine the importance of the response chgnges.
