... Or to borrow a phrase "We've secretly replaced her regular coffee brand with Folger's crystals. Le's see if she notices." I was up at 4:30am (don't ask) Sat. and remembered I'd put the wife's car up on ramps to change the oil Friday evening (ended up passing out from exhaustion at 8pm). So since I had a few hours until work and she'd need the car later in the day, I changed her oil (2.slow '06 Golf). Previous fill was M1 0w40 with a NAPA Gold filter. This fill was the same with the addition of a can of MoS2. Finished the oil change and let the car idle for about 5 minutes while I cleaned up my mess and checked for leaks. I went and filled it with gas for her, bought a pack of smokes, and then took it for about a 15mi ride. Noticed that it seemed "perkier"/more rev-happy towards the end of my drive. Went home, parked it and went about my business. Didn't tell her I'd changed the oil. When I got home from work she asked "Did you do something to my car? It seems to have more get-up and go. It certainly revs faster and more smoothly." I told her about adding the MoS2 to which she said, "If that's what's made the difference please keep using it. Is it expensive?" She laughed when I told her it was $5/can at NAPA. Yes it's not exactly a scientific double-blind study, but considering she noticed the difference without knowing what I'd done I think its pretty convincing (albeit anecdotal) evidence that MoS2 is definitely worth the $5 entry fee. She's going to closely monitor the gas mileage for the next few weeks to see if there is a significant change. Minor Note/Tip: After putting in the can of MoS2, fill the can up with oil and shake/swirl it around and dump that in the engine. There ends up being a lot left clinging to the can and this seems to get most of it out.