I recently acquired a 3/5 drop kit that was removed from a 2012 Silverado that I cannot figure out who's components it is made up of. I thought it was a MaxTrac kit but I emailed them and they verified it was not one of theirs. It's definately not one of the big three and doesn't look like a Crown/Spindle-Source/Ebay kit either. It could be a hodge-podge of parts and that's ok if I just knew whos parts they were. The part numbers on the components are as follows:

Spindles – GM D 07P
Springs – RAR 251310
Flip kit saddles – 401360
Shocks – DTM2000G / Q13 224

And a picture: