Did it with an aftermarket already, there is a thread about it on here. Used a viper remote start w/D2D capability and the DBALL module using the toyota TL4 firmware.
With the factory remote start I believe the car shuts off when you unlock it and you have to start it again.
If you have any questions PM me or message me on Facebook.
I forgot to mention I did this on a manual RS7. Use a relay to bypass the neutral safety. There is a tech doc from DEI which is linked in the wiring information on Directechs based off of my install (I was the first one to do it).
And doing the install on a push button vs key does make a difference as the key is 40bit encryption and the PTS is 80bit. The wiring on the PTS is different also.
Saying a car is "stanced" is like saying that after you pour your morning coffee, the liquid is "cupped".