I just took out the factory front speakers on my EG civic sedan. I dont have a ruler, but they look to be 4". However, They were screwed into a plastic housing, and this is bolted to the door frame in holes that look like they would fit 6" or maybe 6.5" speakers.

So basically, will 6 or 6.5" speakers screw straight into door frame, or do they require an adaptor also?

I know its sort of a car audio question, but is specific to civics only so posted in this section.