I think it's the cheapest fuel additive I've found per gallon including shipping. I burned through a gallon of it, two ounces per tank, on my last car (an APR Stage 3 Golf R) and it ran smoothly and smoked somewhat less under WOT with BioPlus in the tank. I've never had a fuel system issue on a car, but I've always run a maintenance product of some sort (FP60, FP Plus, BioPlus, SI-1, Soy Ultra, etc.) in every car I've owned. Maybe it helps, maybe it doesn't, but it's cheap in the long run and my track record seems positive.
--Matt