Most of the videos I watched went with ground and keyed ignition only. I ordered one too (still waiting on it) and was wondering the same thing. Looks like we need third wire for garage door opener memory.
Redlt4, I'm curious if gps from your phone works with your setup? So your setup only starts bluetooth when you play something on your phone? When you stop whatever is playing, does it go right back to the radio? One last question, did you use the constant power or an ignition source from key.