I would like to give feedback on using MoS2 in my 2004 Passat. So far I am seeing around 3% gain in mileage in 100% city driving. If interested the details are here about my methodology:
Impact of using LiquiMoly MoS2 on fuel economy (2004 Passat) - TDIClub Forums
Also I no longer see small spots of oil from time to time on the driver side of the engine where the car gets parked (garage or driveway).