When I saw this thread earlier, I noted the one on ECS was the OEM one, but I decided not to reply. Technically, there were two versions, a 1.35mm version and a 2.8mm version. I have the the thicker one so I didn't want to comment on the quality of the one ECS sells because it is the thinner one (if their OEM part number is correct):
1J0698930 - 1.35mm
1J0698931 - 2.8mm
With that said, my thicker one is awesome and has saved me a few times after running over some pretty gnarly things on the road. My only issue is that my TDI guru complains when he has to remove it due to the weight

And, it required very minimal modification to the existing side skirts to fit.