New member, long time reader. I registered just to answer your post because I had the same issue.
I have a base 13GT Cab (vert) automatic that I installed the premium cluster with track aps and 18x10 rear wheels. The best I could get for the 0-60 was 5.0. No matter how I tried launching, I could not get the tires to bite. Last weekend I installed BMR LCA with the relocation bracket, and man what a difference. I still can't go WOT from the get go, but I can get 70-80% even in 40F weather. With that change I was able to consistently get 4.7s on launches this weekend. The transmission is set in "S" and I am not doing the manual shifts as they are not quick enough to prevent redlining. I am hoping that when the weather warms up I can go WOT and get the 4.5s. My thinking is that a tune to set the 1st and 2nd gear shifts to 6,900 rpms can get me another .1 and then 3.73 gears can get me to the low 4s.