using the 107 hp from the 09, figure 15-20% loss to the drivetrain, so we have @ 85-90 hp at the wheels.. adding 6 hp at the wheels would be a 8% increase, if you could get another 3-4 hp with some exhaust (rear muffler delete) then you would have close to 1o% increase in power.
if thats corrected to the flywheel, its still a a 5-7% claim. even though the corrections to flywheel power are off, hoping they dynoed it stock for the comparison.