Every time I shut the engine off, but leave the accessory power on, and then restart the car, my x910bt needs to reboot. Is this normal? Seems crazy to have to reboot the thing all the time. Just wondering if there was anyone else who has a work around for this.

This is normal. When you start the car, the power circuits to all accessories is momentarily interrupted so all power is available to the starter.

On a similar note.... We have an X710 in my wife's car. Last week we stopped to pickup some takeout. My wife stayed in the car and I left the key in the Accessory position. When I got back in the car and started it, the X710 rebooted and asked for the startup password. It had never done this before, but usually I turn the car off, this is the first time I can remember that I turned the key to Acc and then back to Start without turning it all the way off.

A good amp cap placed in-line with the ignition-on feed might solve that problem.

This same situation could cause problems if you were to hook up an iPod and then start the car while the VR cataloging was being done. At least I think thats what screwed mine up. I had to use a different iPod to force the 920 to rewrite a new VR catalog and then back to my iPod to get VR back.