6.5" in the front. Component sets are plentiful, so you will want to go check them out at your local audio stores. Depth is an issue and you will probably need to make some spacers or buy them online. I would do a search for that because I am too lazy
4.0" or 5.25" for the rear doors. The larger will require a little modification on your part, but many have done this install. I just went with a 2 way 4".
That should get you started