Fortunately Active Autowerke is giving the N62 some love with a very reasonably priced $499.00 ECU tune. The tune is available for 91-93 octane fuels. For manual transmission cars, the rev limit is raised.
Horsepower gains are 8 peak wheel horsepower as shown on the conservative Active Autowerke Mustang Dyno. Peak HP does not tell the whole story as there are significant torque gains through the curve. Peak torque is increased by 15 pound-feet.
Expect greater gains with bolt on modifications to compliment the tune. Dynograph of a 545i flashed with the software below.