its 3.5" up front and 3" in the rear by the seats. all the way in the trunk by the hatch you have 3" also.......
I took all of mine out and replaces them with eclipse speakers
and a 4 tweeter component set.....I added 2 12" kicker comp vr
in the hatch......sound sick.....can hear me coming from a distance
My 1990 stock speakers were 4" I'm pretty sure. I had Thomas Kenyon's guys over at Custom Sounds make me some custom mounting plates for a pair of Focal 6.5" mids and I had the tweeters flush-mounted. Keep in mind this did get rid of the factory enclosures, but it sounds phenominally better, much more bass. I can't wait to hear what it sounds like when I get my PPI amp in a few weeks.