I'm not sure what advice you're looking for but here are a couple of tips.
Watch their video, it's pretty clear for the most part.
Their original instructions didn't mention how to take apart the front shock. I see the video addresses it much better now but the threaded end of the shock screws off. Clamp the shaft with aluminum or something that won't score the shaft and then use a heat gun or torch to heat the threaded end and it should come off fairly easily.
On the back it will go much easier if you remove all the bolts holding the brake line brackets (they only remove the one closest to the wheel). Removing the brake line bolts lets the axle drop a couple inches further down and will make getting the springs in and out easy. I've used two floor jacks to hold both sides of the rear axle up and then you can raise or lower each side independently.
They take the top bolt off the rear shock to allow it to drop. I've always done it with the lower bolt removed. I'm not sure if that's easier or not but it's worked fine for me.
Earlier install videos said to remove the passenger's side bolt holding the torsion bar. You may need to do that but it can be a pita to get lined back up and get the bolt back in. It seems to work best to reinstall the bolt once you're completely done and the truck is sitting on the ground. When I helped a friend put new springs in we ended up using a ratchet strap to pull the bar back in place far enough to get the bolt in.
Good luck, it's really not that hard if you have all the correct tools.
Disclaimer, my opinion only.
Suit and tie lift. If you're going to roll around in the mall parking lot, that'll work great. It'll probably level your truck up, but it'll jam up your suspension.
They tried to sell me something like that at the dealership.
Try driving one at the dealership that has been leveled first, and if you can find a friend that has a 3 in lift like my king suspension, with new upper control arms, to correct the geometry, I went with Total Chaos, and upgraded the rear springs to dobson 819, you'll see a night and day difference in the way the truck handles.
I don't know what you're going to be doing with your truck. But if you're going to be doing any real off roading, and adding any kind of weight, you'll wanna spend the extra 5k.
Best of luck.