We have dyno tested the conversion on an E28 M5. The result in doing a direct comparison of the MAF vs. AFM meters was an increase of 18 hp and 18 ft-lbs. of torque at 5,000 RPM referred to the crankshaft. We also tested performance with a custom free flow exhaust. After mild recalibration using the ARC2, the exhaust added another 25 hp and 27 ft-lbs. After all modifications, the M5 made 315 hp vs. stock of 256 hp.