I cant look into your shader network, so I dont know, but did you made diffuse and specular ibl too? How it is in Marmoset Skyshop. The diffuse part of it looks similar as a "fake GI" to me. So I find it really cool.
DX11 mode is on but its not the latest version.Later I'll try it with the latest UDK, I just need to download it. I also made an IBL mat a few weeks ago and mine can work with "pre-made" cubemaps ( you import the sharp and the pre-blurred cubemaps) and it can use real time cubemap actors with real time blur that is similar…