Thank you for listening.
Tesla ought to sell an after market audio upgrade package, labor and materials, to be done at an SC. It should be similar to the garage door opener installation. My guess is it would be priced north of $1k since additional amplifiers are required.
I would not trust a non Tesla approved installation.
I would gladly give Tesla $200 per year for Premium connectivity. No materials or SC visit required. Just a flick of switch. Elon can put that money towards video game development. ;)