I've had a spark booster fitted for about 4 weeks now. I found that the engine runs much smother I was told to remove the factory plugs and fit a vgroved plug better spark. With the power there's more power down low and up top. I found no more lag and no engine surge I was told I don't need the fuel booster because I have a herrod fuel pump fitted if you would like ask me more question I will be at afd this week in the f6 owners area just ask for Dave or just ask me on here .