I have a 2013 Sport. The sound in the Sport is honestly not good. I would love to replace all 4 door speakers, but also was interested if the Sport has the empty spot already created where the sub is in the higher up models. If so, it appears it would be relatively easy to add a sub to fit in there. Has anyone done this or know if it is possible? Through some research I found on other models, the sub is behind the passenger rear seat. How is that even accessible? I know the seats fold up, but not sure how to remove the back part to check. I would only add this if the spot is already available. I don't want to put it under the seats as others have done because I often fold both up to transport things. My only other question would be could I replace all the speakers and even add a sub by keeping the stock radio unit? I'm old school and don't like or really need anything newer, but I understand the capabilities of this unit might not be able to handle better powered door speakers and a sub. Any thoughts?