car speakers?

Anybody know speakers that can be used in the BMW 3 series. My local installers have all told me you have to go back to the dealer to get replacements. I want to upgrade as long as I am replacing. I know nothing about it but the main rear speakers have this strange 3 wire connector. Help! please! sorry if this is a threadjack.

Mechans, I'm working on my 325i. It's a challenge...

Mechans, which year/version 3 series do you have (E36, E46, etc)? Check out roadfly.org, & do a search, &/or ask your question there.....I'd also like to know as I have a friend with a '93 318is who's looking for speakers.

I have a '98 M3 (E36). My car stereo guy has proposed a set of MB Quart speakers. He has mentioned that there is a tricky situation where if he uses
one model, he will have to cut into something inside the door and build
something to hold it, but if he uses a different model, it will fit in there with no problem. I've read different things about the sound system in BMW's. Some say the speakers are fine and would sound a lot better with better amps and sub-woofer.

I really appreciate the feedback thanks. I have the 1998 328i (E36). I was also told that the cutouts won't hold commercially available speaker baskets. I had a new crossovers and amp (50wpc x 4) using the same source CD player and preamp elements but bypassing the factory installed amp which was trick for the installer. He couldn't think of any speaker that would "fit" the cut outs. I looked and found this odd tri-ended Jack which makes no intuitive sense in terms of home audio unless it was simply a coaxial rig. Keep those suggestions coming if you know how to use the jack it would be a start. I think I could figure out a way to hold the speakers in the rear in place. The kick panels have very shallow set ins. With the door tweeters I may have to just say uncle and order new ones since the new amp blew them out.- Embarrasing but true that such a great car would be such a pain to change a tweeter and upgrade the rear main speakers.