Turns out they are 6.5 round speakers mounted in 6x8 custom Bose adaptor plate. I'll post a pic of the speaker next week. Not what I expected but not a big deal. I also decided to go ahead with the Infinity Reference isntall.
Today I finished installing dynamat and the speaker in the passenger door. Also, I have the speaker and half the dynamat done in the driver door. I went with 6.5 Infinity Reference coaxes instead of 6x8s because Best Buy was out of 6x8s.
I used the Metra 72-5600 speaker harness adapters to connect the speaker. The package says these are for Fords but they also work for 04+ Mazda 3s. Best Buy also had pretty decent adapter plates to allow install of 6.5s into a 6x8 location. I had to modify the adapter plate and the speaker opening in the door a little bit to make it fit. I cut the tabs off the adapter plate, and I had to dremel the door speaker opening a little bit in order for 2 of the tabs on the plate to fit. Nothing major. I wish I had pics but the wife has the camera.
I tested the sound with only the passenger speaker installed and the driver speaker still using the stock Bose. Fading/balancing all the way to the Bose and then all the way to the Infinity, you can really tell a difference in the mids/higns with the Infinty speakers...a very noticeable difference.
For the serious audiophile, this upgrade probably wouldn't be enough. But, if you're just looking to improve the mids/highs, this is an easy and inexpensive route to go. Cost was about $125 for the speakers, speaker harness, and adapter plate. You can get the speakers cheaper online but I didn't want to wait. My wife bought me two dynamat door kits off of amazon for about $100 shipped. I'll have plenty to do all 4 doors...and I'll have enough left over to some other areas...maybe the trunk.
One last 'also'...I installed a Pro Clip iPod mount and bracket. Not cheap but it fits well and looks good. It mounts your iPod by the climate control knob within easy arms reach. I ran a mini-stereo cable from the aux-in under the console to the dash. It will work well for my needs since I don't need my iPod solution to charge my iPod. I'll post a pic when I can.
Hope this helps.
