Hello all!
I have been searching all over the place for information about replacing the stock head unit with an aftermarket and keeping the stock bose sound system. I have been hearing all sorts of different and contradicting things so I just want to get a bit of guidance about this. First of all this is what ill be using:

1999 Audi A4 quattro
Bose premium sound system

Adapter/Wiring harness: Audi Car Stereo Radio Kit Dash Installation Trim Bezel with Bose Wiring Harness | eBay

Head Unit:
Boss Audio 722CA Single-DIN In-Dash CD Receiver with Front Panel Aux Input and Full Detachable Front Panel at Onlinecarstereo.com


Now I'm picking this head unit because I'm assuming I will need 4 pre-amp outputs for the wiring harness I am using correct?
Also I keep reading that the stock system uses a low impedance speakers and amp of something like 1 ohm. I also read that you have to get a head unit to match this or else it will blow the speakers and amp eventually.

Is this true? or will this Wiring harness take care of that?
And if this is true, how do I tell what head unit I should use?

Is there anything else I will need besides this to have everything work like its supposed to? I love the way the stock system sounds, but I need a head unit with an AUX port to play pandora. Thanks alot guys!