Oh trust me. I’m not upselling the “premium system” in these trucks.The "Bose" system in the ZR2 has paper cones, a terrible amp, and a weak subwoofer buried in the center console. The $600 for the add-on above includes the enclosure, speaker and amp. "This subwoofer system includes a high-efficiency 10" big-bass subwoofer with integrated 200-watt amplifier." If you want a quick plug and play solution, these are a nice addition. If you want a much more legit audio system in your truck you need to swap out all the speakers and do a high quality amp and woofer in the back. The head unit also has a very basic EQ. Any new system would massively benefit by adding a sound processor also. That swap out would cost $1500-$2k, but could run up to $4k + if you really max it out.
I personally purchased it because it is an OEM appearance plug and play “upgrade”