The Revtek kit comes with a longer bolt and 2 sleeves to space out the bracket for the rear brake lines. You are not extending the actual brake line only the bracket that they are attached to.
But I will jack up the 4runner to make sure the lines have enough slack and check the sway bar issue...
I installed the Revtek lift on my 2006 4runner and only gained 2.5 inches in height. I also experienced a top heavy / floaty feeling when driving.
I installed the new FJ coils and shocks yesterday (and the Revtek Kit) and gained another inch in height. The ride quality also increased...