HHO generators are real and some of them do work and can greatly decrease our dependence on fossil fuels in a number of different ways.
Having said that I don't think anyone except the auto manufactures themselves or someone in collusion with them can market any type of device for your car. Based on the market research I have done you can not make money in the after market area. If you build a new car with this tech built in then you could blow the doors off.
IMHO we are not going to see XYNH make it anywhere but I do think there is money to be made on the stock play. I say flip this as often as you can.