Yeah, skip that hack kit from Newton. Its made from about 40 bucks in materials. Those aren't spring packs, they're just stacks of carbon steel bar, he even admits it in the description. The billet blocks are just chunks of aluminum, probably 6061 which is soft as hell, off the shelf u-bolts, and his pivot drop, WTF??? He gives you 2 donuts and longer bolts. Its all hack and junk. Get a nice sky hanger setup, or a add-a-leaf kit from a reputable dealer.
Buy from whoever, but I got my kit from Summit Racing for $300, its a add-a-leaf kit, it gets you REAL leafs, heavier u-bolts, and a real drop pivot bracket. The ride is nice and I think I made a wise buy. Did I look at the newton and the likes before I bought? Sure, and then I looked at them in depth and thought about the engineering end and I realized I needed to start making these kits cause they're all about money and nothing about quality for the purchaser.
We're not trying to be down on ya, we all just want to see you be happy in the end with a great truck that rides great and is SAFE!