replacing speakers in 91 sl500
 

I'm going to replace the speakers on my car and don't know what sizes or how many speakers are in there.I know there are 2 in the door and 2 tweeters behind seats and looks like speaker screens in the dash area.I'm getting fuzz noise--pretty sure the mid woofers are almost shot.I'd like to replace with dynaudio--but not a budget for those--so I'll stick with mb quarts if I can,I have not taken door panels off, so I have no idea what kind of job it will be to swap speakers out, nor do I know where the amp(s) are located, headunit is being replaced with a new pioneer unit/ipod access. I'll probably be adding a 12" fosgate sub in trunk too.