I used Android Auto for a good 6 months with no issues and switched to Car Play. Haven't ran into any purple screen/issues at all during my ownership of the car/phone
I can answer 2 of your questions:
1. The center valve is not present in the touring edition.
2. Drone sound is not present when driving at highway speed.
AWE has released their new exhaust for the FL5 CTR. I went with the Touring edition since I want street usability without drone. Hope this video helps!
Took her to autocross again today on the new wheels and tires. Turned off traction for the first time ever and spun out at the first cone xD
Still learning how to drive the car fast. It's a riot!