I'm getting ready to cut my Street Shield. I experimented with many different angles and nothing made it any better. Sound was better with no shield. I decided after to try the Laminar Lip. The BMW R1200GS for 2005-2012 fits the NC Street Shield EX. I chose this over the MRA Vario Screen, primarily because of cost.
My first attempt was to mount it as high as I could at 2.5 inches above the street shield. It was worse, increased turbulence even more! Tried changing the angle several times, but the shield was better without it. I lowered the lip to be even with the shield hoping for improvement. It still was worse than the shield by itself.
Bottom line, if you are considering a Laminar Lip for your CB1100, have a second thought. I had high hopes, but to no avail. I'll be cutting my EX soon.