Depends if you put the hammer down in 2nd gear at 20mph, or 4th gear at 40mph. Any situation that causes the MK5 to wheel spin hands the 7R an immediate advantage.
On the motorway there isn't a lot in it. At those speeds, you need shed loads more power than your rival to pull away convincingly. Creeping away gradually doesn't constitute an arse handing in my book. Weight, gearing and wind resistance can affect that. What I class as a win is when the leader pulls several car lengths very quickly and the gap keeps growing. For that, you need +150hp at least.