I used the mentioned Focal IC VW 165 speaker for all doors. In the rears, due to the consensus that the rear speakers would be to bright from having over driven high frequencies out of the VW EQ crossover curves, I installed an L pad resistor set according to the articles in
L-Pad Calculator on the rear tweeter speakers of the 165 coax set. The screenshot shows how I used the second box calculator and inputed 2 identical 1 ohm resistors and got a dB output from the calculator. I state that the db reduction to be between 7 and 9 db, due to the impedance being either 2 or 4 ohms for the Focal speakers. They say 2 ohm on the box, but my research showed most VW speakers are 4 ohm.
The resistors are in the second picture, and are bought on Amazon for 5 ish dollars. They are sound rated 10 Watt 5% accuracy resistors, you cannot use low power electronics resistors. These are kind of big and bulky, but were fast to get, cheaper wire wound 10 Watt ceramic resistors are available that work perfectly fine, but were on a longer delivery.
I breadboarded them up according to the schematic in the above link, then wired them back into the tweeter speakers(the non insulated wires in 3rd picture) tidied up the wires with tie wraps, hot melt glue gunned to parts of the speaker support to stop any rattling.
They perform quite well, and I am happy.
I also tried a failed experiment, trying to have a very clean install and never get into those door handles again, I purchased a set of foam speaker door enclosures and installed. They totally killed the bass. I notice some nice sound dampening tape behind the speakers on outer door skin also, so they must be crudely designed as a sound enclosure and need the entire door cavity for best effect.
I also took advantage of the door handles being off and available on a bench and vinyl wrapped all the door handles and arm rests with carbon fiber look film. My first time and I got better at it as I got all 8 of the pieces done to get rid of the super shiny black finger print grabber.
