The Echo is just in the car for the ease of showing everything in one shot and working. Its home is on my kitchen counter. The only thing that stays in the car is the MX Bluetooth and the Pi. That's it.
I also am getting a lot of comments on security concerns with either the way the can-bus is implemented, or this car starter is implemented. I will write a blog post on this soon. TL;DR Seriously, it's just as safe as a keyfob and can only be used on your local network at home.