the bose system won't have "2 wires" for each speaker, it will have a minimum of 4 I think they have more if I recall correctly. it needs to have positive signal, negative signal, positive power, negative power, and I think they have a turn on lead and some other **** as well.
regardless, if you WERE going to swap in a bose you would want to get the speakers that came with the head unit. The Z speakers won't fit the vert. They are a pain to bypass. The bose headunits suck anyway.
Just trust us on this one, buy the entry level pioneer or sony, they are LIGHT YEARS ahead of the factory bose crap from the early 90's in features and performance. You don't have to understand all the technical crap, just let me say it this way: You will get good FM reception, great CD playback, you can have a remote control or an IPOD input, detachable face for safety, expandability if you ever want to add components, and it will have enough power to rock some door speakers loud enough to hear over the windnoise.
The factory stuff is pretty "meh" in all aspects.
Crutchfield is a great idea you can tell them what you have and they will give you the plug in adaptors for your speakers AND your headunit. for a beginner its the next best thing to taking it to an electronics store and letting them do it. You will pay more than if you buy the components on ebay and install them for yourself, but for someone at your level of understanding it may be the best choice to let crutchfield do it. And they have excellent tech support over the phone.
or another option check out forums like
http://www.elitecaraudio.com ... read up on stuff before you buy anything.