When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Firstly blocks on the front end is a bad idea, under braking the extra torque will warp the leafs and change the caster.
Now with the fabtech kit, it relocates the track bar mount so you reuse the stock. I would hope all of the box kits follow this idea, but I don't know that for sure.
Hpefully you are talking about a coil spring spacer.
You will not have to change the trac bar, or lower it if you raise it only 2 inches.
You will only have to lower the trac bar to stay parallel to the drag link. If the drag link has to be lowered with a drop pitman arm because it is too short to reach, and maintain a proper turning radius, then you must also lower the trac bar to prevent bumpsteer. 2 inches is alright.