Got the DG sigma 5 and BFI knob installed this week. In hindsight, this is really something I could have done myself. Reason I say that is I had to crack back into the engine bay for shifter adjustment (more in a sec on that)

Sigma 5
-Well constructed, solid piece of metal
-Came missing the bushings for the side/side piece and they overnighted the correct pieces. Great service and near instant responses from them (i think its only a couple people there)
-Jim responded instantly with questions about adjustment after my initial install.
The shifter is super crisp and defined from stock. When installing, the instructions say to pull all the slack out. Thats what my shop did but unfortunately that was entirely too tight. That makes going into first/5th entirely too hard. I pulled the intake back out and gave it just about 1/8 inch of slack and now its PERFECT. im a shifter snob after having the JHM short shifter kit in my s4 for so long, but this is pretty darn good and a fantastic improvement over stock

BFI knob
Got the GS2 schwarz fro my shop (NGP in lorton, VA) which conveniently meant no wait for production vs ordering online. Knob is fantastic, weight is perfect with the DG shifter as well. I opted for the BFI coin after weighing the option of the gate pattern coin. The fit is perfect and no "clicking" while shifting from near-perfect fitment.

Yes, there is a bit of notchiness but everywhere Ive read says wait a week or so it mellows out as the friction surfaces wear into place.

These two are a great combo together. I will post pics of the knob tomorrow. Feel free to post personal experience/suggestions/questions in this thread.