I don't know if the wheel well for the Sierra's are different from the Silverado's, but you can run 35s with just a 4" BDS. I saw 4.5" of lift and have no rubbing issues and didn't have to trim. I did however go 35x11.5 and not the usual 35x12.5 but BDS claims you can clear them too. I just don't like too wide a tire. This is all on stock 20's of course. Hope that helps. This is the second time i go with a 4" lift; it's the ideal lift for me.
Alex, did you have to remove the grille? I'm installing a CAI on mine soon and would like to do what you did here but I don't want to remove the grille...heard it screws up the front camera.
I've used Auto 4WD on my 2013 Silverado with a BDS lift and had no issues as well. As for this 2019 Silverado, I plan to use it as well. BDS pretty adamant about you being able to throw whatever you want at this suspension and it will take it. I'm sure Auto 4WD will be fine.
I think I have the same issue. Thought it was bass at first too but now I think it's the window where it rolls down. Whenever I press the plastic down, it stops. I haven't heard it in a while since I started playing around with it. Not sure what to do if it comes back.