i have the bose stereo system in my 91 and the rear 6x9's are starting to go. i can get an ausome deal on some polk speakers but i was told the wouldn't work with the bose system. is this true?

 

Did you change your head unit or are you still using the Bose one?
I changed my speakers and my HU to alpine and I had to rewire the entire system so that it would sound decent. Bose equipment is very difficult to work with when replacing components

 

yeah, it will not work without replacing the Bose HU as well.