Don't forget that today's engines have tighter bearing tolerances. The crank exerts pressure on main and con rod bearings but with little tolerance and too thin an oil film, bearings stress, displace oil and block oil passenges leading to failure.
Gear drives, chain driven cam shafts and uneven firing order all invite damaging engine vibration causing early valve train fatigue and loss of HP.
A lighter flywheel/damper in theory should only let an engine rev faster/freer. It should not affect HP, but will have a perceived HP increase at the track because the car will accelerate faster by reaching peak power quicker.
