I finished my installation last night for the two front speakers. I used 6-1/2" Jamo speakers, $9 each from Paarts-Express. This is a Swedish made speaker who 15-20 years ago tried to compete with Bose by offering lineups against the Accoustimass. Good sounding but never really gained ground due to lack of name recognition.
Here's the speaker
Sound is very good quality. Tight bass and sound can be loud when cranked up. The thud thud thud of the bass can be felt strongly when your arm is resting on door armrest.
Some notes on installation:
1. The plastic garnish on the door window switch cluster breaks *very easily*. I snapped the plastic on both Left and Right. I think my screw driver is too thick for the job. One might be better off using a butter knife. It can also break when installing so be really careful. I will post picture later. Brand new, the part costs around $300 on the driver side and $85 on the passenger side.
2. The replacement can be made without completely removing the door panel. After removing all the screws and tabs, lift below and raise the panel enough to remove the speaker mount/holder (4 brass screws using socket #10). All work is done outside anyway (except if you are adding EDead).
3. The MDF seems too thick as an adapter. If you look inside the panel cavity before removing the speakers, there's only about 1/4" to 1/3" clearance between the speaker and the door speaker plastic grill. One may use a 1/4" birch or oak plywood. Make sure you use GE Silicone II or similar when assembling the speaker to the plastic speaker mount/holder to close air gaps.
Thank you Zgone for your post and all the others who installed ahead of me.