I have these H&R springs for my M3P when it arrives in a couple of weeks. Happy with the pics of the cars fitted with these and that they give an equal drop to the front and rear.
The springs you currently have fitted on your AWD as you correctly say are a different Tesla part number, meaning your car will sit higher than an M3P, but I think the shocks are the same. By fitting the H&R 28659-1 springs it will drop your car to the same level as my M3P once fitted, so in effect you will see a larger drop than I would overall (drop is 30mm on an M3P, so your car will drop 30mm plus the difference between an M3P and AWD, so 40mm).
Hope that makes sense.