6" of tubing after the maf correct.
I had mine out since the incar retune from overkill, i told him the screen wasn't in there, he said it was fine and he did 1.5-2 hours of tuning and said the readings weren't fluctuating and the car was easy to tune.
got my 800 km on a full tank of gas without it, did it make a difference in power? I don't think so but hasn't caused me any problems.