Aftermarket HU...Bose adapter question

[jroth142]

Hey guys, I'm looking into upgrading to an in-dash dvd/nav unit (avic-d3) and I just wanted to make sure I'm looking at the right adapter for the BOSE speakers. Does the OEA4-4 channel sound right? You will also need an aftermarket wire harness as well right? I'm pretty sure I saw crutchfield selling the combo for around 40 bucks. Also, I've seen many people say that you really need to replace the stock speakers as well when changing head units, but will it actually sound worse with the new unit and original bose speakers than before? I'm not looking for a lot better sound by just changing the head unit, I just don't want it to sound worse. Any other info/advice would be great!Thanks in advance