NO, they don't work. Most are just cheap resistors that fool the MAF into thinking the airflow is different than it really is. The ECU eventually figures it out, and fixes the fuel/air mixture. It's not worth the risk to the engine.
John Griggs did some work trying this idea, but using real test data and calibration. Check his old posts and you should be able to find it. This was on his 3.0 enigne.