Have the CDA-117 and am happy with the sound for the sources I mainly use it with (ipod, sirius). However, am considering switching to a double-din unit primarily for looks and a more user-friendly interface, especially for the ipod. Does anyone have any thoughts on how the CDA-117 compares to the 4300DVD (or a similar HU) from a SQ standpoint? The ipod sounds great through the 117 with its burr-brown DAC handling processing and I'd hate to lose noticeable SQ by switching. Equipment is as follows. BTW, I do not need nav and would like to keep cost around ~$500 which is why I'm considering the 4300DVD. Thanks in advance.

HU: Alpine CDA-117
Amp: JL HD900/5
Front: Polk MM6501
Rear: Polk MM651
Sub: Sundown SA12 (1.75 cubes @ ~30hz)