Any improvement would be great in my opinion. I have an '89 525i and I am only getting about 17mpg right now, even though I'm trying to baby it or take the freeway more. I probably need to replace the sensors in my car.* I'm not getting any knocking even at WOT on regular and it's been about 104-107 degrees the last couple days... but then I have 8.8:1! What do you have?
*I've disconnected the sensor that runs into the exhaust in the past and I don't think it changed the way the car ran nor the mileage. But that may have been before I had to replace the engine so I'll try disconnecting it and see if my mileage changes. If not, does it sound like a bad sensor?