I have the Bose Gold in my '90 and just repaired the amps (my brother is an electronics technician and got repacement parts at work and did the work at his work bench after hours

). I looked into several aftermarket stereos and was told you have to use a power antenna adapter, a specific wiring harness, and you have to run all new wires to the speakers. The best advise I got was from Cructhfield who also said I would need to fabricate new mountings for the speakers. They offered pretty good advise, but could not be specific on how to route the wires.
Most of the local shops agreed that you had to completely rewire the speakers. I believe (but am not certain) if you do not have the Bose, it is much easier and you can yse the existing speaker wires. If you look on Crutchfield and email them, they usually give pretty good advise for your specific car and with other cars I have upgraded stereos on their instructions were right on.
Good luck and let me know how it goes because in a year or two I will probably trash the Bose.