TwistedPhil
+1y
That first link you posted was for an AIM Industries rear link kit. I'm not going to go into why you shouldn't buy that, because you can spend hours on the web getting other peoples' opinions about AIM, Chassis Tech, AirRidePro, Godmothers... whatever they're calling themselves this week...
The other problem with that kit is that it's only the rear end assembly. You still need tanks, compressors, valves, front bags & brackets, lines, fittings, wiring, switches...
You can get name brand, high quality components for the same price as the knock-offs on ebay, and you'll be WAY happier with your truck when it's done.
Like others on here have said, count on around $1200-1300 for a basic setup, and close to $2k with all of the fancy bells and whistles (bigger compressors, more tanks, etc.).
As for the amount of work, it will depend on what size wheel you plan to run, and whether or not you have to have your truck FLAT on the ground.
Keep looking around in forums like this one, and you'll find a lot of information.
Good luck!
-Phil at FBI