Hi Nick and Ursula –Well, I told you that if the system worked to my satisfaction that I would provide a testimonial, so here it is.I'm very pleased, in fact extremely pleased, and downright ‘stoked' about the water injection system. My problem was pinging, and no matter what I did, and believe me I tried everything I could find, it seemed to have no effect. I could eliminate the pinging only if I severely retarded the timing but, then the overall performance suffered so badly that I could barely pull away from a stop.I found that for my car, it's a 1979 MGB, it's still best to run premium fuel, and straight distilled water. I know that some people mix the water with alcohol, and I have tried it myself but, for my car, water only has proven to be the best. I have gone to the next hotter plug, and I have found the optimum timing for all the variables. It took a while, lot's of road testing but, now…wow!Before the water injection, about the best I could get before pinging started was only 2700 RPM's…which is insanely low. But, now I can easily get to 3500 out of first, 4500 out of 2nd and, easily to 3500 or 4000 out of third! What a difference.I never track mileage on paper but, my wife and I take certain drives repeatedly, and I have a pretty good ‘feel' for fuel consumption, and I would say that your estimate of 25% increase in fuel economy is accurate. Today, we drove round-trip from Oceanside to Cardiff and used very little gas, probably less than a quarter tank.Nick, I'm very pleased, and I'll happily recommend this system to anyone.