Do you have two sets of speakers in the rear deck? If you do they are usually 5 1/4. Now taking the speakers out is kind of hard because u have to take the rear seats out and then pry up the rear deck to pull out the speakers. Now if you have the four speakers in the back they might have a factory crossover because u only get low pass out of the 6x9's and high pass out of the 5 1/4's. check it out and let me know I can get u the doc's.