Custom Diesel has a similar kit that ships for $100....and is made in the U.S.A. I got about 2" of lift from it...very happy with the kit.
Another thing to think about, is you may need a track-bar drop bracket or an adjustable track bar, as it will likely un-align the axle.
The biggest difference between blocks and a mini-spring pack is they have a center pin that goes through them and the actual leaf springs so they can't "pop out" like a block can on the front. (Why most states make a block in the front illegal.)