The HGP Golf R 3.6 swaps are pretty darn quick themselves. We have seen several videos of HGP 3.6 VR6 twin turbo Golfs in action lately including one going door to door with a 458 Speciale as well as beating a tuned GTR and EVO. With horsepower in the mid 700 range it is no slouch and a very fast Golf. The Golf is the lighter car here but the E63 has roughly 100 horsepower on it and more torque.
The Golf puts a great fight and the cars are closely matched. The E63 wins the majority of the runs but in run 5 where the Golf gets a better start it pulls and maintains its lead. Run 6 is probably the best of the seven runs as the cars both get good starts and are door to door until higher speeds when the E63 opens up a roughly two car lead before hitting traffic.
The final run is interesting as the E63 gets a lead only for the Golf R to come on strong. Heat soak affecting performance at this point? Likely the case as the Golf pulls away.
Interesting set of runs as they show how outcomes can vary based on variables as timing the start or at what speeds the runs take place affect who wins with cars this close. Two very fast cars here and thank you @Vasily1 for the videos.