The LCA,s really need to be in the right plain after lowering. Brackets will help this. Tire compound will also help. I have Nitto 555 G2's and they work very well.
I second this. I lowered my 2013 1" with Voigtland springs, and just recently installed Whiteline lower and adjustable upper arm. And it is super easy to break loose my rear tires. I am supposed to get my Nitto's this week, but my LCA relocation brackets from Steeda were on back-order and only just shipped, so my rear arms are in the stock location. I did a lot of research on the relocation brackets and was dubious as to the need with only 1" lowering. But from what I researched the LCA's should be parallel to the ground when the car is sitting on the tires, at least that was the Ford engineers intent. This should promote a neutral position for best overall handling, ride, etc. Having the arms located so the axle mount is lower than the frame mount is supposed to create a leverage situation where the axle wanting to rotate will "push" up on the body / pushing the tires down into the pavement for more traction. This is why they are used for drag racing. In the position mine are at with 1" lowering, the axle rotation pulls down on the body lifting the rear axle and breaking loose the tires. Now, I can't speak to lowering the axle mount for drag racing as my relocation brackets are still in transit and I haven't personally tested this, although the premise is sound. But I can confirm that my traction is definitely reduced in my current configuration. I mainly plan to drive on street and the local road coarse when it's completed, so I am only looking to make my rear arms parallel to the ground. I will be happy to report back after this weekend and tell you if they work as advertised.