Question - is there a reason why soldering is being recommended here? My understanding is that in automotive applications the preferred method is crimping since a solder connection will fatigue and break before a crimp due to vibrations and movements.

 

Either was is fine. I would recommend the crimp connectors that shrink and seal with a heat gun if you want to go that route

 

'Cuz a lot of us are old.

The connections being referenced are of the 'crimp the conductor together and wrap it with hockey tape' type.
I would not have expected that on a car that was $90k new.

I stopped doing the equivalent 'twist the wires together and wrap it with electrical tape' before I got out of my teens.

I learned to solder, and learned to do it reasonably well.
Correctly done, properly shrink wrapped, they are as good as a crimped connection, as long as the joint isn't flexed.
For these the wires are in a bunch, and under the carpet and pad. They don't move

I think crimp connectors would be a viable option, as long as the ends are properly sealed. Either with heat shrink or using the connectors that have it 'built in'.