Generally, you'll find:
* Front Doors: These are *most likely* 5.25" or 6x8" speakers, but could potentially be other sizes depending on the sound system. The depth of the speaker will also determine what you can fit; shallow-mount speakers are often necessary in older cars.
* Rear Deck/Package Tray: This is where things get even more uncertain. It could house speakers of various sizes, again depending on the factory options, and whether it uses a dedicated speaker assembly or just a cutout. You may need to remove the speaker grilles to see the mounting holes and measure the available space.
Therefore, you can't just say "X size will fit." You *must* physically inspect your car's speaker locations to determine the dimensions (diameter and mounting depth) before selecting replacement speakers.
Once you have the measurements, you can look for speakers of those dimensions. Many aftermarket speaker manufacturers, such as JBL, Pioneer, Kenwood, Rockford Fosgate, and Infinity, make speakers in various sizes that should be compatible with appropriate mounting adapters or brackets if necessary. Always check the speaker's depth to ensure it will fit within the available space in your doors and rear deck. You may also need speaker harnesses/wiring adapters for a proper connection.
