I may be able to get my hands of an old set of top-notch MB Quart 6.5" door speakers. Is that the factory size for the 91-92's? I was wondering, is the metal of the door the same, just a different speaker enclosure/grill? Any way that I could make the bigger size fit? Anyone fit a speaker bigger than 5" into the old 4" location? Any help would be rad.