I recently replaced a Dinan chip with an E.A.T. chip in my 1990 535a. Not only did I get a more balanced power band (Dinan was most noticed at higher rpm) but my mileage increased. The Dinan yielded 16 - 17 mpg city and about 20 mpg highway. The E.A.T. chip is giving 17 - 19 mpg city and +/- 25 mpg highway. Thanks Mark!