A sub will make a pretty big difference in the audio quality, so I would definitely get one. A good installer may be able to fit one into a cargo wall, as the Highlander has a lot of room. As for a separate amp, it all depends on how good you want your music to sound. An amp will also improve quality substantially. Given the size of the Highlander, an amp will also help the speakers fill the interior space with audio.
I got a 2002 Toyota highlander (got the v6 with a few options added) and i wanted to put in a new stereo, so far i have a Sony MEX-BT2600 cd deck and im going to get that installed in a few days. I wanted to change out the speakers as well so would it be better to get two sets with or with out a sub? (i wanted it to look pretty much factory so i dont really want to have a box sitting in the trunk) or just have a set of speakers with decent bass? if so what kind of speakers would be recommended and do i need an amp?
Thanks ahead of time for your responces!

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