These adapters will only work with 6.5" and 6.75" speakers if you skip the Honda mounting bolt which prevents the basket from sitting flush on the adapter. I replaced the Honda mounting bolt with a M5x0.8/30 mm stainless steel countersunk machine screw. Then I countersunk the hole in the speaker adapter so the top of the screw is flush with the mounting surface. Such an easy fix - too bad the engineers at Scosche are so lame. If you are going to Dynamat the doors, the adapter will have an air-tight seal to the door. Otherwise you will want to use some kind of sealing material between the adapter and door to prevent rattles. Finally, you will have to use a Dremel and cutting wheel to cut off the two metal protrusions at the bottom of the speaker hole in the Civic's door. They interfer with practically any 6.5" speaker basket. The adapter will still be able to hook into the bottom two slots like the factory speaker does. Other than all that, these adapters are okay and I'm using them in my install.
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