[gprixgtp]

Did they say why? I believe the bose speakers are 4ohm. There should be no conflict with an aftermarket head unit. My door speakers are either bose or monsoon, I have yet to actually be interested enough to find out. They were the seperate 4 rear speakers and the front seperate tweets and mids. I have an Eclipse head unit now and am running a JL amp to them and have no probs. I have changed out the rears to a set of Pioneer 5ways but only because one was blown prior to the headunit switch. The front speakers do surprisingly well. Good enough that I can wait till I find the speakers I really want to replace them with. As long as they are not 1ohm speakers there should not be a problem. 2ohms could cause the amp in the stereo to get a bit hot, you may even consider a small 4 channel amp and run the speakers off of it. Then any heat at all would not be in the dash. You don't need a big amp, a good quality 75watt per channel will make better sound quality then the stereo amp as well. It is small enough to hide anywhere too if you don't want it in the trunk.
Anyway verify the ohms on the speakers and go from there.