I have a 1999 buick century custom and i want to replace the factory speakers in the car?

the buick century comes with four door speakers,most likely three by threes and two six by nines. what should be the best match up of speakers to put in there?I have a 1999 buick century custom and i want to replace the factory speakers in the car?Go to www.crutchfield.com click on outfit my car and it will tell you exactly what will fit your car.

http://www.crutchfield.com/