New head unit, preserving factory Bose

[03PathfinderSE]

Sorry for yet another Bose question, but I can't seem to find the information I need when searching. Have an '03 Pathfinder with factory Bose and a single DIN Pioneer head unit with only one pre-amp output that I want to install in it. I really don't want to rip out the factory Bose amps and speakers. From what I have gathered, Metra makes two wiring harnesses, one without pre-amp wiring (70-7550) and one with (70-7551). I understand there is also a Nissan/Infiniti Factory Integration Adapter from Scosche (CNN03).

I have the 7550, but I from research I see this may not work correctly as I'll be feeding amplified sound to the amplifiers (instead of pre-amp), but I've seen others write that they have had problems with the Scosche CNN03.

Can I make the 7550 work, or should I go with the CNN03, or is there another solution (short of ripping out all the Bose)?

[BoostMyQX4]

Get your self one of these and your done, thats what i did to replace my Bose unit for a single din pioneer and added an amp and a 12" woofer for bass, im a happy camper.

http://www.ebay.com/itm/PAC-NISSAN-INFI ... 02&vxp=mtr