Isn't Harmon Kardon more known for their receivers than speakers? I've heard that the system is good for mid-range vehicles. Really dependent on how much the upgrade will be and if the stock sound system is really that bad.
Looking forward to your feedback on the audio system because given Kia's past they haven't been know for the most well insulated cabins which can lead to sound leak, diminishing the quality of a high end audio system. In that case dynamat or a similar material should help.I love music, and plan on getting the GT2 AWD with the HK system. Can't wait to feel it.