Today I installed the GFB Mach 2 T9111 and a Pierburg valve since it seems like the thing to do. Everything is working perfect and I will update if anything changes. I ended up getting the 2 Pierburg valves out of curiosity. I bought the Ford (7.02087.05.0) and the Volvo (7.28197.16.0). I did not get the VW design ( N75 Race Valve BOV Solenoid Valve Upgrade Kit (Pierburg) – N75 MotorSports ) since I did not want a jumper harness adapter. These valves all have the same basic design with the differences being outlet/inlet diameters, plug design and possibly the internals. From left to right these are Kia oem, Volvo, Ford
N75 has said the VW one is the best and most dependable. He might be right, I figure for $40 I can buy 3 of the Volvo ones if I had to. If anyone has more to add to this, please do since I am still not sure why some people need this to prevent a cel and others don't.