upgrade 2000 eldorado esc stereo

hello,
just bought a a 2000 eldorado esc, and found out that the 2000 eldorado etc came with a better stereo, a bose system, which i don''t have, my question is can i install bose deck, the bose door speakers with amps, and the rear bose speakers with amps,
will the harness work on the deck/ stereo to my car harness, and will the wireing work to the speakers, my mechanic might think it will work because he thinks when the car came off the assembly line they wire it for both then  leave the unused wire there
i can buy a package deal off ebay for the bose system to my car at a fair price , but i want to make sure i can do it and that the part''s are compatible, thanks grock