So as the title says started to upgrade. Here is what I have found so far 3 3.5" speakers in the dash with the same speaker also in the rear doors. Front doors have a 6x9 there is about 3 3/4" of depth to work with. On the rear parcel shelf there are 2 6x9 which I believe are the same as the front door ones although the connectors are different, these 2 6x9 are on either side of an 8" round sub woofer then there is a self powered 8" sub woofer in the right rear corner of the trunk. All the speakers I have measured so far which are the door speakers and the 2 6x9 on the rear shelf and the 8" shelf sub woofer are 2 ohm. My first upgrade coming are five 2 way 3.5" with a 1" soft dome tweeter to replace all the dash speakers and the rear door 3.5", these are a 4 ohm but they have a fairly high sensitivity rating and because I tend to add base in my current system and a bit on the highs it should be workable. Will post results after I get them in. I have insulated all the door panels and all of the trunk with Frost King 1/8" foil foam insulation which has tightened up the base a lot and removed a lot of road noise as well. I intend not to replace the amp or the self powered sub in the trunk, may replace the 8" sub on the parcel shelf. Have some JBL gt 6x9 2 ways coming for the parcel shelf and the front doors which are 2 ohm. Have to do some sweep frequency tests to see what signal is fed to the various speakers unless somebody already knows what the factory is doing for cross over points.