I'm sure you appreciate all the responses and Congrats on your IS! I too just purchased one. A 2013 with DCT. I had an 07 n54 and a 12 n55 and both had JB4. Ran e50 on map 5 and loved it! I installed JB4 on my IS with 900 miles, taking it easy, however. I'm at 1150 miles this am and can't wait till 1200 + miles to see what she has!
I thought about Cobb over and over. I stayed with JB because of Terry's response time and support. Either way you can't go wrong!