That kit is basically just the BDS kit being sold by their sister company (Zone). I believe this kit will have the issues that Mike (El Cid) noted in the way the rear lift is achieved, and the reason BDS stopped selling it.

Also, it's really not any cheaper than the SL because the SL comes with the AEV module whereas Zone requires you to purchase it separately. See Note 4:
4. Although unusual, if ESP problems persist the AEV EGR module can be used to dramatically reduce the issues.
So... since the AEV module costs ~$300, add that to the price of the Zone and you're really not saving any money. I'd rather go with the SL, especially since they've refined their design.