You have to build them completely. They come in little baggies. But after you put one together, the rest are a cakewalk. If I remember correctly, the instructions were pretty good, I could follow them. I found it easier to put one completely together to figure out what I could do all at once on all parts to make it go by quicker, but I think it only took me 30 minutes to throw them together.
Just make sure to follow the oil wieght recomendations. I went a little heavier and broke a disk once. I backed it off from 70 to 60 and haven't had problems running 4 on either my savage, or my maxx that no longer exists...
60 is actually a little heavy on my savage. If I cared, I'd probably drop it to 50 and use the navy blue springs that come in the kit to get a little more plush feel. As it is, it rides pretty stiff (60 wieght with their black springs), but it can take 6 foot drops all day long.