Installed a pair of blue (1,000 #) Sumo Springs today. Fairly easy job. The only thing I did that wasn’t in the written (included) instructions was putting some blue locktite on the bolts attaching the springs to the included mounting plate. The remaining nuts were nylon locknuts. I did not use the included spacer. When the job was complete and I lowered the rig I saw that the springs were touching the rest on top of the axle. The manufacturer suggests having 1/4-3/4” gap between the plate and the spring when the truck is unloaded. I have a Diamondback bed cover, tools, snow chains, tow chain, etc in the bed which probably adds up to 300+ pounds. Drove around a bit and the rear end felt a little stiffer but nothing to get excited about. Can’t wait to pull my trailer.