Im about to purchase the BDS 6inch lift for my 2005 F-150 4x4 and there are two different setups to chose from the Block & Add-A-Leaf setup or the leaf spring and i was wondering what the difference was and any advantages or disadvantages to the 300 dollar upgrade?

 

The lift block is the least expensive, but may contribute to axle wrap. The add-a-leaf is only slightly more expensive, but will make the rear suspension stiffer. The new springpack is more expensive, but should ride better.