Hi Kevin,
Hope you are fine and your installation worked out ok.
As I was also searching for better speakers that fit the stock openings I went ahead and pulled out the stock door woofer to measure the exact dimensions of it and the opening (still missing the data for the stock tweeter though). Maybe this is also interesting for some other people here...
So, here's what came out of the door...
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Now, the dimensons:
Diameter woofer grille: 165mm
Diameter woofer basket: 158mm
Diameter inner door opening: 130mm
Diameter of screw ring: 142mm (virtual ring where the 3 screws sit)
From these measurements, I would say that probably only very, very few 6,5" woofers will fit without further modifications.
Problem #1 is, that most 6,5" woofers require an installation opening of approx. 140mm or more due to the size of the common baskets. I have not found any 6,5" woofer, that would fit the stock installation opening in the door (130mm).
Problem #2 is, that the stock grille is exactly 6,5" in diameter. This is unusual as well for 6,5" woofers as normally, the grille is larger in diameter than the woofer itself. So, the grille coming with your new 6,5" woofer will not fit into the door (since the outer door opening to flush mount the grille is exactly 165mm in diameter). Now, you could use the stock grille with a standard 6,5" woofer by just mounting the grille on top of the woofer. In this scenario, you would have to drill new holes into the woofer basket to reach the stock screw holes in the door. This however would severely damage the surround of the woofer since the screws of the stock grille sit on a smaller diameter. The better way would be, not to screw the stock grille back into the door. Instead, just pushing it into the carpet opening until it sits on the woofer might work. The grille could be fixed with a few drops of black silicone. However, you would need to make some screw dummies to cover the screw holes in the grille. For the new 6,5" woofer you would have to drill new holes into the door flange, of course.
So, it seems that only 6,0" woofers would fit without cutting. Unfortunately, there are not many of them existing. So far, I only found them offered by Kicker and Rockford-Fosgate. But maybe you know a few more?!
Sounds like you made good progress. Pictures would definitively be great! As you had to use the Focal grilles for the woofers: are they flush with the door panel or do they stick out a bit? I am worried about the k. nee bolsters that might get hit when closing the door if the grilles are not flush?? 
