This is completely a loaded question...if you wanted to buy all the components from one company, I would say Cage...their long arms are the bomb, their dual shock mounts are also very trick and look great and their shocks also receive rave reviews. I have heard nothing but good about their springs. I will be running their arms, dual mounts, shocks. I opted for deaver springs from a different supplier...I also got several other smaller components from various places.
The reason why this is a loaded Q, is that there are some other components needed to pull off the susp. lift that either Cage doesnt sell or that better options are offered by other vendors. A track bar axle riser bracket is a better option than a drop track bar bracket...there are a couple of options for the axle riser brackets, but the best I have seen is the WH one ( or you can fab one yourslef--do a search). Extended brake lines, and a few other things will be needed and I dont believe Cage offers those smaller parts. IF you get the "complete Cage kit", there are a few things that come with it that you may or may not need, so it really just depends on how far you want to go. To get the best (at least among the better) suspension components as far as travel, articulation, handling, on-road performance all in ONE place...you are looking at spending about $1700-2K for all the parts--even as a kit. You can buy such a 'kit' form JBG or WH, BUT some parts you may want (to change out or upgrade to) may or may not be available through that particular vendor as well. While its often nice to 'buy it all at one place'; it may be a better idea to source the different components from two or three vendors...but ultimately its up to you, how you drive, where you will drive, how much you want to spend and what your end goals are. Just some food for thought.