No the engine was not removed! It was all done on a normal rolling road, I don't know the intricacies of how it was all calculated. I think the 20 % increase is the interesting bit. Regarding noise, at 3000 revs at 6 foot from the car the decibel level was 100, at 5000 revs it was 106 decibels. That is the medium system. No I'm not into computers sufficiently to record it! The loud system needed ear protectors at 5000 revs!! Chris P DOC UK -----Original Message----- From: dcsj4465 [mailto:dcsj@xxxx] Subject: [DML] Re: SS Free Flow Exhaust (and photos) At the flywheel hp? Did you actually remove the engine from a car and hook it to a dyno? Or, Was this done on a wheel(chassis)dyno and corrected for drivetrain losses? Can you be more specific? Please define Medium loud as opposed to the standard American exhaust sound? Is there any chance of downloading sound clip of the system running at idle and revved up?