I added a powered sub (Infinity BassLink 10") to beef up the bottom end of the stock sound system, and it was enough of an improvement for me that i put everything else I had planned to do on hold indefinitely (upgrade all speakers and H/U). That was a year ago and I'm still happy enough today with the sound that I've taken the other upgrades completely off the To-Do list. Maybe some time in the future, but not the near future.