Opel Corsa D rear speaker adapter

Here is my version of rear speaker adapters for 13cm (5.25") speakers that have "ears".
If your speakers are round without ears you should check mcles011 thing
https://www.thingiverse.com/thing:1153291

Before starting the project, please note! Not all editions of Opel Corsa have speaker lines in the rear doors. In fact, for my Corsa, I had to run speaker wires in the rear doors and also, from the doors to the head unit. Moreover, you have to pin the wires to the door connector. For my car, the pins and wires in the female connector where already in place but the wires where stopping somewhere before the head unit so I had to trace them and splice new wires to the headunit.
The pins you need are 4 male MQS Quadlock.

If your head unit doesn't have pins for the rear speakers you also have to add pins or change the connector.

You will also need speaker terminal spade connector (2.8mm for the female and 4.8mm for the male terminal). I like connectors because they are easy to plug and unplug in case of maintenance or if you indent to change speakers. Also, soldering the speaker terminals voids the warranty.

You will also need some self-threading screws. 7pcs M5x10 for each door.
Your speakers might include some of the mounting hardware but it usually doesn't fit all cars.

I also suggest the you buy some plastic door clips before you open the door panels because some of the old ones will be broken or cracked.

I have included regular and tilted speaker adapters. I highly recommend using the tilted adapters with coaxial speakers(built-in tweeter). The tilted design will guide the highs to the ears of the passengers and make the sound much more defined and clear.

If you indent to place cheap speakers and have to do all this wiring just don't! In my opinion it is not worth the effort.
I used Hertz cx130 with sound deadening(sound deadening is highly recommended, I did a comparison with and without the deadening and it makes a HUGE difference)