It would be interesting to know precisely how direct injection improves the previous EFI systems. In other words when the old mechanical systems (ex. CIS) were set to Air to fuel ratios that were optimal for the given condition, i.e. cold pressure, warm pressure and boost pressure depending on the amount of boost you had, there was not all that much coverage for the different ranges. The EFI systems fixed this and provided a more linear supply of power, making cars more drivable and safe as well. So, while knowing that Direct injection is an improvement, it would be interesting to know "how linear is made even more linear." But in any case, good to know that Audi and VW are at the cutting edge of this technology.