Enhance Sound system in SE/base models?

[naturoses]

How to improve the sound system in SE/base models in Highlander without removing my head unit but still want a better/best sound like bose/Sony etc., Also, should not involve drilling and holes.
This highlander's radio sounds similar/ exactly same to my just traded in 2010 Rav4.
Thanks

[az_lander]

If you want to keep the stock radio and enhance your sound, one way would be to use a 6 ch line output converter for adding outboard amps to your factory system. You will need to upgrade the speakers as well. There is some work involved. It depends how much you are willing to spend.

[naturoses]

Originally Posted by az_lander

If you want to keep the stock radio and enhance your sound, one way would be to use a 6 ch line output converter for adding outboard amps to your factory system. You will need to upgrade the speakers as well. There is some work involved. It depends how much you are willing to spend.

Thanks for replying.

First, the reason I wanted the stock base radio is to keep original looks as welll as factory 6CD changer. In order to keep the looks, I can also buy Rosen Nav, BUT, I cannot afford it at this moment of time and also feel $1500/- is too much for the that stuff. Why mention Rosen Nav is because you have mentioned that it improves sound quality on yours.

I cannot DIY, hence, have to ask Professional installers. I really do not know what to ask as well. I would like to know what to ask them technically and how much is reasonable to spend to get a quality sound.

Do not want to be cheated because I have abosultely no idea about the tech. details but I am only longing for a better/best sound then my base stereo.

Thanks again