TLDR; sometimes less can be as much as anyone needs. And if more is needed, our drivers are up to the task.
Update December 2022: This is all still 100% correct.Front SoundStage Speakers
In short, our front soundstage upgrade focuses only on the speakers atop the dashboard, and here's why (in broad strokes); this is the only area of the Jeep where we can control an image and therefore accurately reproduce sound. Given that we're introducing not only 20mm tweeters into the system, effectively "adding" two speakers, we've also meticulously reworked the midrange drivers that are already located in the dash to better disperse their respective "frequency responsibilities" through both material design (6061 aluminum curvilinear cones, inverted surrounds, slightly less efficient to further bring the midbass into the soundstage) as well as combining their acoustical characteristics with the silk dome tweeters.Lower Dash Speakers
The speakers located in the lower dash are functioning as mid-bass drivers, which are producing a range of sound that's omnidirectional, meaning those frequencies aren't needed to be guided in a single location. They're functioning in more of a "feeling" capacity than an audible capacity. Without changing amplifiers and using much larger midbass drivers (in non-Alpine systems - the Alpine systems have incredibly robust midbass drivers from the factory), you'll be hard pressed to make any noticeable improvements in this location given they're firing directly into your knees/floorboards.Sound Bar Speakers
The speakers in the sound bar are obviously already behind us, and given the movement of sound through the cabin and that our ears are tuned to sounds in front us (hence a "front soundstage"), we see little if any reason (which is of course debatable, but after 20 years of designing loudspeakers as well as audio systems of all types we've developed a sense for what really works for most people) in spending money on speakers that aren't effectively improving the actual presence of a soundstage in front of us (think of a band at a concert).
We spent the better part of 18 months dialing in this upgrade, and after extensive modeling and actual prototypes installed in the rear sound bar we just don't see (or hear) a valid reason to add speakers/spend money on speakers behind you. Sure, you can "hear" some additional sound coming from behind you but your ears/brain can't process it in such a way that you'll perceive any improvement in what you're actually hearing.
In summary, we know that for MOST folks this simple, impactful upgrade is all they'll ever pursue for their audio upgrade needs. It brings life to the music that simply isn't there in either the Alpine or non-Alpine factory systems.