I am not really happy with the sound of my Symphony unit (2007 A4 3.2)....not talking about being loud or a lot of bass but simply the quality of sound....my old Altima had after market everything (speakers, HU, small sub).
I kept the sub and plan on putting it in but don't want to be messing around with the speakers so that's kind of out of scope.

Would you say that changing the HU (from the standard Symphony) to AVIC D3 (which I just like because it will fit perfectly in and has red disply) will provide me with significant improvement??

I am looking for any input/opinions before I spent $900 on a HU that doesn't improve much....in terms of sound quality.

THANK YOU

SQ is more affected by changing speakers than it is by replacing the head unit. You'll probably notice a more linear response but nothing drastic.

It's tough to try to compare a full aftermarket system with something pieced together with aftermarket and OEM parts.

...it is not a solution for better sound over the factory unit.

I would look into the Alpine W205 or Eclipse 6610 for better quality sound.

The W205 is in the same price point as the AVIC-D3 so I wouldn't expect it to be noticeably better. The advantage the W205 has is that it can be connected to one of Alpine's processors for a big improvement in SQ. I kind of wish Pioneer would come out with a processor similar to the Alpine PXA-H701 or Rockford 3sixty.2 because the features and user interface of the AVIC-D3 is slightly better than the W205.

As far as the Eclipse goes, that is a significant step up in price and with 5V outputs and 24-bit DACs, I think that would be a step up but you probably wouldn't be able to tell the difference with OEM speakers.

..one item though.

The Avic D3 and the W205 are not in the same price point. The W205 has no NAV at that price. The complete unit with the Blackbird NAV is almost double the D3.

...they showed a whole bunch of new stuff at CES I heard...we'll see what comes to the market.

overall, its about the same. all my bose speakers were shot to begin with, but its relatively the same audio quality