I have no advice as to a better solution, but the reason that you are NOT hearing reports of tapping into the CD Changer input sounding awful is because there aren't any, your situation is different if not just broken.

I read your post to advise trying the boost-treble EQ-setting of an i-device as it finally returns some of the air in the upper reaches (8k boost? unsure). You start with that and adjust the (gawd-awful) included treble and bass bands from there, resulting in acceptable playback from iPOD/PAD, which is to say Much better than the dash CD (even with the compressed thin-ness inherent in iTun-ified sound)

3k mi trip, from an ex-sound guy, it was no longer terrible (low volume, of course). My personal reference is audigy low-position-mic flat and klipsch RFs or (preferably) my old magneplanar Tympany.

__________________
carpe` cevesi
knf

01 topaz e53 3i 5m 120k mi =
$9.7K + $2.4K when seller says "needs nothing" (131K)

Drew Cary: I love driving stewpid in hella thunderstorms.. I roll stop-signs.. get pulled over, the high-school cop says, "Do you know why I pulled you over?"
I say, "Sure.. do you know why I did it?"

2012 Election: Congress has determined that government beatings of all taxpayers must continue until morale has improved

Gone: '67 Galaxie LTD 2D aqua, 72 Pinto, 76 Elite, e12 track.. long road