I have a 90 Eldorado w/o Bose System and I'm looking for information on replacing the front speakers. Crutchfield doesn't have any data and the Metra catalog says 6.5" but I've read 4" and 5.25" on different places. I'd like to confirm information before I take the door panel apart. Have any of you fellows replaced front speakers on an Eldorado of this year range? Thank you in advance.