This is a pretty old post so I don't know if the original poster will reply. I have a 2" lift on my 2017 Impreza Sport and we didn't have to lengthen the brake lines when we installed it. My kit is Subielift OZ, but it should be similar to the ADF kit.Nice! Did you need to disconnect and lengthen the brake lines? That's the only part that sketches me out.
However, a not funny story is one of my friends didn't reconnect the brake line properly so it was rubbing against the rim and it broke while I was going 65 on the freeway. Luckily I didn't hit anyone and was able to slow down and pull over to the side. I was NOT happy. So double check the brake lines after installing.