Have been using Ecorive on my 500 Lounge C for two weeks and my best score is 63. Frankly, it takes all the pleasure out of driving my 500 so I decided to stop using it. Now I just stomp on the gas a go and break as hard as I want to. So far it's cost me about 1 MPG. That is well worth the cost to enjoy the fun of driving this neat little car. Anybody agree?