Once you cut them and have them out and open to the air then you already start degrading them.
I take it you just are not going to twist connect them together, you would have to soder them, the problem is if you heat up the signal wire you could burn it out, I have seen them go crispy for a couple inches after a soder point, making them useless.

If your this determained to do this then why not just use an LOC and a line driver, you can tap the wires in the trunk and not have to pull your deck out at all.
If your willing to spend the money then the RF 360.1 or the JL audio Clean sweep are designed to give you the same SQ as aftermarket HU's

 

Well I was hoping for actual dvd audio as well as the ability to play mp3's on a dvd, but, at this point, maybe I'd settle for just being able to play mp3 dvds.

 

very few car audio players actually play dvd-audio. sadly. but theres very few dvd audio albums anyway

 

Seems like it is easier and cheaper to just setup my own custom-built computer with monitor than doing it any other way.

 

if u want a screen theres a few that will but none that arent a flip up or double din