2006 bmw m-3

there is a bunch of speakers in these vehicles. the last m3 i worked on had 10 speakers and a factory sub in it. of course there will be at least one amplifier in this vehicle and sometimes you will have crossovers built onto some of the speakers. a couple of times i have actually removed the factory crossovers and used them on the aftermarket speakers but it kind of depends on what equipment you go with. if you get tunable crossovers then you might be better off using that. good luck and hope this helps.