The S65 V8 at 4.6 liters is capable of 441 wheel horsepower. So, on paper, this actually makes for a fairly good race especially with a DCT M3. Yes, the C5 Z06 has a weight advantage but the M3's higher redline makes for a gearing advantage. So what is the problem? The 20 inch Hartge wheels the owner chose to put on his car which are basically boat anchors sapping power. The Hartge badge on the trunk clearly not making it up for it.
Furthermore, the 441 wheel number for a stroker M3 came from an RDsport setup, not Dinan. Dinan uses a fairly mild tune and has yet to demonstrate as high of dyno numbers with their motor. To really take advantage of this setup the M3 owner needs to ditch the wheels, get a new tune, and also look into Schrick cams as the stroker moves the peak of the powerband to the left. Much more horsepower is there to be had by moving the torque curve to the right towards redline with a more aggressive profile similar to how this Z06 gains power with its cam setup.
Enjoy the race, but seems silly for the M3 owner to spend all that money on the motor only to limit it in other areas.