just lowered my Allroad. Do I need to adjust camber/castor, and how easy is this to do on an Allroad.

and is optimized for that. Constant use at level one cuts into tire life. By changing the 402 calibration my car is set between 1 and 2 at level 1. My tires now live 2x as long as they used to at level 1. And with 255 45 18's my wheel wells are filled. I have found that while level 1 minus looks cool, the ride and handling are badly compromised. YMMV

various ride heights? I STFA but couldn't find anything. Thanks for the info, btw.

get the alignment shop to set the toe and equalize the camber at level 1. This may induce some squirreliness at 3 and 4 at higher speeds.