Putting xenon in fogs will not pass MOT . Also leds can possibly show faults on dash or flash every 30 seconds as the car checks for faulty bulbs
I have on my a6 c6 h7 halogen bulb with a blue tint. It gives white light 🙂
I fitted new springs a month ago . They will do down a bit after a month or so
And showroom or not they have the weight of the car on them so the hight will be diffrent when you mesure the spring with and without load on them
By logic things go down with age ... 😂
Just remember when you will buy new rear sprinds the car will sit higher that before. They will get a bit lower after a month or so but it will be still higher than now.
I dont think anyone here would be able to help with this one .... air ride on audies are complicated 🙂
you need a vcds scan first to checl for faults as they may point out that is wrong .
And get it to a specialist to do a pressure test on the system