When a single part in the car does not function properly you would get tensed. When you plan for the long drive you would obviously send the car for service post which you would clear the service charge. As is suggested by service people you would also spend on the replacement of some important and crucial parts that are worn out. But this service would not indicate that it is time for you to upgrade your woofer. You may not even pay attention to this accessory of your car as you would not have heard to the music in the car for a long time because of struggling with the traffic on the road. The other way could be you did not take your car out for a long time as you have been managing the travel to and from office by booking the cabs.
So, the reasons could be several for you not able to assess the quality of the woofer that is presently being used by you. If this was your situation for the last trip with friends, then at least now plan to buy the subwoofer boxes that would bring perfect clarity in the music. The quality would make you feel so fresh. Though you are hesitant to enjoy music previously because of the irritating sound that it creates when you drive over hard roads, now you would prefer to listen music that comes from new woofer boxes. Journey in an old car with new woofer boxes is still possible unless you do not plan to drive the mountain roads.
To make the journey enjoyable and not tiring you should pick the woofer boxes that do not get heated up too fast. When the design enables the cool air to reach every crucial and delicate parts of the woofer, then the chances of overheating the entire device would be less due to which the woofer would perform as expected and thus would entertain you throughout your journey. So, be happy to buy the woofer than to think of it as a burden on you.