ok im sure as us capri owners have noticed that our doors arent as water tight as they should be, i have noticed down the years of owning mine i have a speaker maginet rust and come loose from the basket, and i have had adaptor rings get wet like this one
this can be a problem because it can damage your speakers and give you poor sound quality,
i noticed that our doors make very poor enclosures for 5 1/4 even 6 1/2" speakers
Another thing i came to notice is that our doors in the stock location only have about 2 1/4 inch of space untill you hit that brace so for any good upgrade of speakers you really have to make some kind of riser for them, so lets start with that,
use MDF or Birch 1/2" or 3/4" thick and make a speaker ring and screw it down to the stock location
next if you have a problem with water you dont want that ring getting wet, i used shurtape AF100 foil tape and surounded the ring to seal it from the elements and also add some strength so it does not split
now a good thing to do is seal the speaker off from the elements and give the speaker a smaller enclosure to produce better sound quality is use a baffle, what i used was DEI Boom Mat and i then put it into the speaker ring
you will need to poke a small hole into the baffle for the speaker wire and using some tape seal the hole up.
Finally screw down your speaker and put the door back together and start jamming out to some loud music with AMAZING sound quality and AMAZING bass response !!