I have been wanting to make an EFIE for a while and i didnt want to spend alot of money so this was perfect for me. The parts cost about $10 at radioshack. I went to hook it up to my Saturn and there was only 1 O2 sensor wire so it was pretty simple . At first when i started to test drive the car with it on i thought it wasnt doing anything, then i cranked it all the way up and the car started to hesitate and miss so i turned it back down to where it would stop hesitating and i set it at like 450mv. That seemed high to me but i just drove along and my temp gauge started creeping up so i backed it down and ended up setting it to 300mv. The car has lost some power but it still accelerates smoothly. I just filled up and i'm going to leave it set at 300mv until i need gas again (unless something happens and i have to adjust it). I'm getting right around 40mpg consistently so i should be able to tell if it makes any difference. I will let you all know the results in a few days.