Thanks a lot for the info!
I really hope there is a decent installer in my area (there are a lot of cars resonating as they drive by which isn't a good sign).
Don't even think if doing custom sound instals on new cars anymore. Those days are over. If you want to guarantee a voided warranty and a ton of car trouble seek out a custom installer to really wreck your car.
An even bigger issue is that installers do not understand how a cars electrical system has changed and now operates.
The demands on the car's electrical system are now massive, especially since going to electronic steering.
The old analog voltage regulation is long gone. Now the voltage regulator is a powerful digital amplifier basically. The switching frequency of this device in my car is 180 MHz!
This results in high frequency contamination all over the power bus, and the grounds as well.
The upshot is that your new custom installation will not likely perform wall and be very noisy.
We have had a couple of post about this already.
We are basically at the point where the entertainment system in modern cars has to be part of the overall design of the electrical system.
Take my advice and don't even think about doing this ever again.