Howdy Ya’ll. I have a 2007 Tahoe LTZ 4x4 with the Z55 Autoride. Its got almost 220,000 miles on it with the OG front air struts and about 30,000 on its second set of rears. I want to put a list of part numbers together for when it kicks the bucket. I know I want to run the Bilstein 5100s that have the adjustable height front shocks. I have some questions: 1) What does ‘preload’ mean on struts? I keep seeing people talk about it but I don’t know what it means 2) for the Z71 NNBS vehicles what was the difference as far as the struts in front and the springs in the rear? As of now what I think i want to do is get new front struts from rockauto and the set of the 5100 shocks from amazon, and have a shop install the Bilsteins set to the 2nd notch for ~3/4” of lift in the front, and order the non z71 non z55 rear coil spring for no ride height change in the back. That way I have a touch more clearance and travel in the front, and no change in the back. As far as resistors, What should I do? Is there a way I can delete the air compressor so I’m not carrying it around? Thanks in advance everyone!