On a stock M112 motor we've seen -3RWHP and .6 towards the lean end on the AFR. Not a smart move at all. Due to the location of the stock MAF the turbulence caused by the air entering a non-directed intake WILL (not may) result in negative consequences. Needswings intake works because it relocates the MAF to a more direct and unobstructed airflow path. The same design is used on the E, ML, and CLK class M112 engines.

Take the inof that I and many others have provided and use it the way you want to.