well we retarded the timing and the f@$^en computer keeps adjusting right back to were it was, did everything by the book. so we just bought the map sens enhancer so we can lean it out or make it more rich from inside the car to bypass the computer. as for the power the hill by our house without the hydro we pressed the pedal about half way to go up it, and with the hydro it's a 1/4 of the way pressed so it makes a big diff when it's on. if you take a .99 big grab bag of chips fill it with gas fumes then light it it makes a little pop but more like a swish sound, with the hydro it's like an m-100 going off. you can watch people on youtube blowing stuff up with the hydro from home made cans and it's pretty funny to watch some of them. you really don't need to do anything to the engine and you have a 30 day money back garentee the kits are made for specific engine sizes, but if your computer keeps readjusting for your timing then you need a map sens enhancer which is only $54 shipped. don't be fooled buy some of the units, we checked on ebay and they are made of plastics and to me that is just not safe when you are making a highly explosive gas. always look for the garentee and how long a company has been around, and if you can find other sources about the company not just what they say also.